Porpoises.] 



MUSEUM OF ANIMATED NATURE. 



239 



ORDER CETACEA. 



The Cetacea are characterised by the conical fish- 

 like form of the body covered with a smooth naked 

 skin, adapted for the medium in which they live ; 

 between the skin and the muscles is a layer of 

 blubber, varying; in thickness in different species, 

 and most, abundant in the Greenland whale, its 

 thickness being from eight or ten to twenty inches. 

 The uses of this layer are various : — in the first place 

 it renders the huge body of these animals specifically 

 lighter than the surrounding fluid ; secondly, it ma- 

 terially tends to the preservation of the vital heat ; 

 and, thirdly, it affords protection to the internal 

 organs against the effects of Ihe enormous pressure 

 to which these animals are subject while plunging 

 deep into the abysses of the ocean. The fore-limbs 

 are modified into flippers, and the posterior part of 

 the body, destitute of hind limbs, is continued coni- 

 cal, and terminates in a broad horizontal cartilagi- 

 nous paddle. On the central line of the upper surface, 

 and generally towards the tail, is sometimes seated a 

 small vertical cartilaginous fin, unconnected with the 

 skeleton. This fin varies in figure, and is often ab- 

 sent. It is partly by the aid of this fin, where present, 

 but more so by that of the flippers, that the cetacea 

 balance themselves in the water, for when dead or 

 dying they float on the side or the back. The mode 

 of progression consists of a series of leaps or impulses 

 produced by the action of the tail, which is bent 

 down and then struck out with greater or less vio- 

 lence, according to the rapidity with which the 

 animal is cleaving its way. By means of this organ 

 it can dive instantaneously, or even leap out of the 

 water, throwing the waves around into spray and 

 foam. In the ordinary position of the cetacea while 

 floating, only the top of the head and part of the 

 back- appear above the surface, their capacious 

 jaws, and also the eyes, being beneath; hence, in 

 order to admit of 'uninterrupted respiration, the 

 situation and structure of the nostrils are modified 

 accordingly. 



These animals are called blowing cetacea, because, 

 in consequence of the structure of the nostrils, they 

 are capable of throwing up jets of water or spray 

 accompanied with a loud noise; this act is termed 

 blowing, and the nasal orifices blow-holes or spi- 

 racles ; they open on the top of the head, and lead to 

 two large membranous pouches seated immediately 

 below the integument. These pouches are recep- 

 tacles for fluid, which, being forced up into them, is 

 prevented from returning into the throat by certain 

 valves furnished with strong muscles, lodged above 

 the intermaxillary bones, see Fig. 1084, the skull of 

 the Dolphin : it is in the hollow at the top of the head 

 that these pouches are placed. The posterior nasal 

 passage is furnished with longitudinal and circular 

 muscular fibres, and opens into the pharynx or back 

 part of the mouth, and into it the larynx rises in the 

 form of a pyramid, and the circular fibres of the nasal 

 passage have the power of grasping it by their con- 

 tractions. The channel, therefore, from the larynx 

 through the posterior nasal passage into the pouches 

 is plain. Now these pouches are lodged, as we have 

 said, beneath the skin, and the nostrils which conduct 

 to them open externally by a transverse semilunar 

 slit, while very strong muscular fibres, radiating from 

 the entire circumference of the cranium, cover the 

 whole surface of the apparatus, and act as compres- 

 sors of the pouches. Let us suppose, says Cuvier, 

 "that the cetaceous animal has taken into its mouth 

 some water which it wishes to eject; it moves 

 its tongue and jaws as if it were about to swal- 

 low, but, closing the pharynx, it forces the water to 

 mount into the nasal passage, where its progress is 

 accelerated by the action of the circular fibres, until 

 it raises the valves and distends the membranous 

 pouches above. Here it can be retained until the 

 animal wishes to eject it, and take in breath. In 

 order to spout, the valves being closed, it forcibly 

 compresses the pouches by means of the muscular 

 expansions which cover them ; and compelled to 

 escape by the narrow crescentic aperture, it is pro- 

 jected to a height corresponding to the force of the 

 pressure." The noise, however, called blowing, shows 

 that the animal forcibly exhausts its lungs of the pent- 

 up breath, driving the air through the nasal orifices 

 which, mingled with the water contained in the 

 pouches, rises like spray or dense mist. Fig. 1085 

 represents a section of the head of the porpoise, show- 

 ing the structure of the nasal apparatus. This ap- 

 paratus is of little use as an olfactory organ, the sense 

 of smell being very deficient. As respects the or- 

 gans ;f sight "we may observe that the eye is very 

 small, and adapted, as in fishes, to the density of the 

 surrounding medium, the cornea being flat, and the 

 crystalline lens globular; there is no lachrymal 

 gland, but the lids are furnished with certain little 

 glands secreting a fluid adapted for lubricating the 

 eye-ball. The external aperture of the ear is mi- 

 nute and capable of being closed at pleasure. Under 

 water the whale hears the smallest sounds, the 

 shghtest splash of the oar, but to sounds in the air 



above, even the report of a cannon, as Scoresby 

 states, it is insensible. Its auditory apparatus, en- 

 closed in a bone (petrous portion of the temple) re- 

 markable for hardness, appreciates only the vibration 

 of water. The sense of taste does not appear to be 

 acute. 



The cetacea, passing their existence in the wild 

 waste of seas, are capable of remaining submerged 

 for a considerable length of time, and the vascular 

 system is modified accordingly, the arteries not only 

 of the limbs, but of the chest and vertebral canal, 

 being singularly plexiform. The discovery of this 

 arrangement is due to the celebrated W. Hunter, 

 who published an account of it in the Phil. Trans., 

 1787. These animals, he says, " have a greater pro- 

 portion of blood than any other known, and there 

 are many arteries apparently intended as reservoirs 

 where a larger quantity seemed to be required in a 

 part, and vascularity could not be the only object. 

 Thus we find that the intercostal arteries divide into 

 a vast number of branches, which run in a serpentine 

 course beneath the pleura (lining membrane of the 

 chest), the ribs, and their muscles," forming a deep 

 maze of intermingled and contorted tubes. "These 

 vessels everywhere lining the sides of the thorax 

 pass in between the ribs near their articulation, and 

 also behind the ligamentous attachment of the ribs 

 and anastomose with each other. The spinal cord 

 is surrounded with a net-work of arteries in the same 

 manner, more especially where it comes out from the 

 brain, and where a thick substance is formed by their 

 ramifications and convolutions; Fig. 1073 repre- 

 sents the arrangement of the arteries of the chest. 



Nor is this plexiform arrangement peculiar to the 

 arterial system, it is even more strongly displayed in 

 the venous ; the veins in certain parts forming im- 

 mense plexiform reservoirs. This curious disposition 

 of the vascular system in the cetacea is, as we have 

 intimated, most probably connected with their habits 

 of diving, during which their respiration is sus- 

 pended, and consequently the passage of the blood 

 through the lungs impeded ; while at the same time 

 they are subjected to a great pressure. Hence per- 

 haps the arterial plexuses are needed as reservoirs 

 stored with oxygenated blood for the use of the 

 system, while the venous plexuses are reservoirs for 

 the sake of safety during the suspension of respiration. 

 The females of this order have two teats deeply 

 imbedded at the lower portion of the abdomen. The 

 stomach is very complicated, divided into several 

 compartments, and digestion is very rapid. 



As these animals have to plough the waves head 

 foremost, a long or even decided neck would inter- 

 fere with their movements, consequently the cervi- 

 cal vertebrae are compressed into a small space, and 

 more or less entirely anchylosed into one mass, to 

 the total immobility of the head, the axis of which 

 cannot be altered without a corresponding alteration 

 of that of the body. It is moreover remarkable that 

 the two halves of the head do not precisely corre- 

 spond in symmetry. This is especially observable in 

 the dolphins, porpoises, grampus, and cachalot. 

 (See Meckel's Anatomie Comparee, vol. iv. p. 361.) 

 The cetacea are all carnivorous, but their prey 

 differs from the small mollusk to fishes and even the 

 smaller of their own order ; and their teeth are mo- 

 dified accordingly. They are divided into the fol- 

 lowing families: — 



1. JDelphmidce., Dolphins, Grampuses, Narwhals, 

 &c. 2. Catodontidce, Cachalots or Spermaceti 

 Whales. 3. Balcenidce, Rorquals and Blubber 

 Whales. 



Family Delphinid/e (Dolphins, Porpoises, &c): — 



1086, 1087. — The Common Porpoise 



(Phoccena communis). In the genus Phocsena the 

 snout in the living animal is not produced as in the 

 Dolphin ; but in other respects the characters are 

 the same. The teeth are numerous, compressed, 

 rounded, and interlock when the jaws are closed, 

 and are well fitted for snapping at and retaining the 

 slipperyprey. (Fig. 1088.) A dorsal fin is present. 

 There are several species. 



The common porpoise is active, fleet, and vora- 

 cious ; it frequents, in troops, the bays and. inlets 

 of our coast, and especially the mouths of rivers, 

 not unfrequently advancing to a considerable 

 distance up their stream. In such places it is often 

 takeninnetsby the fishermen, becoming entrapped 

 while eagerly pursuing its prey. When the shoals 

 of herring and other fish which periodically visit our 

 coast make their appearance, they are harassed, 

 among other enemies, by this active and voracious 

 animal, which revels in the luxury of a perpetual 

 feast ; and as its appetite is enormous and its diges- 

 tion rapid, the slaughter in which it appears inces- 

 santly occupied must be very great. The porpoise 

 is common at the Nore, and few have sailed to Mar- 

 gate or Ramsgate who have not seen these animals, 

 tumbling along, as they appear to do, in the rushing 

 waves. The peculiarity of their motion results from 

 the horizontal position of the tail-paddle, and the up- 



and-down stroke which it gives ; and their momen- 

 tary appearance is for the purpose of breathing, 

 which accomplished, they plunge down in search of 

 their food. In former days the flesh of the porpoise 

 was highly esteemed as a delicacy for the table, and 

 was served at, public feasts ; indeed, it is but lately 

 that it has fallen into disrepute, and been omitted 

 at city entertainments, where the turtle usurps its 

 place. Our forefathers must have had a different 

 notion about table delicacies from ourselves; for 

 few, we believe, would now relish the rank, oily, 

 fishy flesh of this animal. Length about five feet. 

 Fig. 1076 represents the skeleton. 



Fig. 1084 represents the skull of the Dolphin (Del- 

 phinus Delphis), a species celebrated by the ancients, 

 and resembling the porpoise in its habits and food. 

 The aquatic evolutions of these animals, as seen 

 sporting around ships, apparently for the sake of 

 amusement, their varied and rapid turns, and gam 

 bols, are well described by Ovid — 



" Undique dant saltus, multaque adspergine rorant ; 

 Emerguntque iterum, redeuntque sub a:quora rursiis, 

 Inque chori ludunt speciem, lascivaque jactant 

 Corpora, et acceptum patulis mare naribus efflant." 



1089, 1090.— The Narwhal 



{Monodon monoceros). The genus Monodon, of 

 which the Narwhal is the only recognised species, 

 is provisionally placed by Cuvier in the family Del- 

 phinidse. It evidently forms the type of a distinct 

 group. Among the cetacea inhabiting the dreary 

 realms of the Polar Ocean, the narwhal, if not the 

 largest or among the largest, is nevertheless one of 

 the most remarkable: its general form resembles 

 that of the porpoises; it has, however, no teeth, 

 properly so called, but two ivory tusks, or spears, 

 implanted in the intermaxillary bone, but of which 

 the right remains usually rudimentary and concealed 

 during life. The left tusk, on the contrary, attains 

 to the length of from five to seven or eight and 

 sometimes ten feet in length, and projects from the 

 snout in a right line with the body, tapering gradu- 

 ally to a point, with a spiral twist (rope-like) through- 

 out its whole extent (Fig. 1091), where, by an over- 

 sight, the. tusks have been transposed. In its structure 

 and growth this tusk resembles that of the elephant, 

 being hollow at its base or root, and solid at its 

 extremity. It is in the male only that this spear- 

 like weapon, under ordinary circumstances, becomes 

 duly developed, the females (and indeed the young 

 males) having the left as well as the right tusk con- 

 cealed within its bony socket. This rule, however, 

 is not invariable, for females have not only been 

 seen with the left tusk projecting, but the right also, 

 if we may credit the account of Laeepede, who 

 states that Capt. Dirck Peterson, commander of a 

 vessel called the Golden Lion, brought to Hamburg, 

 in I6S9, the skull of a female narwhal, having two 

 tusks implanted in it, of which the left measured 

 seven feet five inches, the right seven feet. It may 

 be added that Capt. Scoresby brought home the 

 skull of a female narwhal in which both tusks pro- 

 jected, though only to the distance of two and a 

 quarter inches, and which was examined by Sir E. 

 Home. Nor with respect to the male must it be 

 supposed that the right tusk never becomes deve- 

 loped, for, on the contrary, instances sometimes 

 occur in which the right tusk projects externally 

 nearly as far as the left ; and there are grounds for 

 supposing that when the left becomes lost, or broken 

 by accident, the right tusk becomes developed to 

 supply the deficiency. Formerly these horns, or 

 tusks, were looked upon to be the horns of the fabu- 

 lous land-unicorn, and therefore they were valued 

 as an inestimable curiosity, and sold excessively 

 dear, till the Greenland fishery was set on foot, 

 when they became more common, and their real 

 nature known. 



The use assigned to the tusk of the narwhal by 

 Crantz, viz. that of uprooting marine vegetables on 

 which to feed, is altogether a supposition. As the 

 male only has this instrument developed, or gene- 

 rally the male, the female must be reduced to sad 

 difficulties in the procuring of food ; but in truth 

 the position of the tusk renders such a use as is here 

 attributed to it impossible. Moreover the narwhal 

 does not subsist on marine fuci, or algae, but on 

 soft animal matters, as mollusks and fish. Capt. 

 Scoresby found the remains of cuttle-fish in the 

 stomachs of several which were opened by him, and 

 similar remains were also found in the stomach of 

 one driven ashore near Boston, 



In general form the narwhal resembles the por- 

 poise, but the head is small and blunt ; the mouth 

 is small, and not capable of much extension. The 

 under-lip is wedge-shaped. The eyes are "placed 

 in a line with the opening of the mouth, at the 

 distance of thirteen or fourteen inches from the 

 snout, and of small size, being about an inch in 

 diameter. The spiracle, or blow-hole, is a single 

 orifice of a semicircular form, on the top of the 

 head, directly over the eyes. The fins, or flippers, 

 are about fourteen or fifteen inches Ions:, and from 



