190 



MUSEUM OF ANIMATED NATURE. 



[Pteropoda. 



kajak in the veiy mm which the clio itself na- 

 vieates. 



The outer covering of the clio ia a delicate semi- 

 transparent soft skin which covers a second lunie. 

 This last is thicker, and presents longitudinal and 

 very sensible muscular fibres, which come from 

 two principal bundles attached to the sides of the 

 neck. The effect of these fibres must be to shorten 

 the general envelop of the body, and to approxi- 

 mate its form to a spherical shape. Cuvier, who 

 gives the above description, adds, that he knows 

 not with what the interval between this fleshy tunic 

 and the mass of the viscera is filled in the living 

 state ; but observes that it is certain that these do i 

 not occupy the half of the area which the tunic 

 incloses ; and conjectures that there may be a 

 liquor diffused there, or perhaps only a (juantity 

 of air which the animal can compress at pleasure 

 when it would sink in the water, and dilate when it 

 would rise. 



The head of the clio is enveloped in a sort of 

 hood, which can be opened and retracted at plea- 

 sure, so as to expose the mouth surrounded by 

 three conical appendages on each side, like little 

 fleshy tentacula. Examined by means of a micro- 

 scope, each of these appendages is seen to be re- 

 gularly and numerously covered with red points, 

 which, when inspected through a lens of great 

 power, are found to bedistinct transparent cylinders, 

 each sheathing about twenty minute suckers, which 

 are capable of being protruded, and acting as 

 organs of firm prehension. It has been calculated 

 that the total number of these suckers upon the 

 conical appendages of a single clio amount to three 

 hundred and sixty thousand. 



Besides these oval appendages, the clio can pro- 

 tnide from its head, through a perforation in the 

 centre of each valve of the hood, two slender horns 

 or feelers, in order to ascertain the presence of 

 food. 



The mouth of this little creature is a triangular 

 orifice armed, according to Eschricht, with two jaws 

 with sharp horny pectinations fixed on a fleshy base. 

 These pectinations are of unequal length, but their 

 points are nearly on the same level, and they can 

 be protruded for the purpose of seizing prey. 

 Within the mouth is a tongue with its tip and upper 

 surface covered with minute curved hooks in regular 

 rows, evidently serving to assist in the act of de- 

 glutition. 



With respect to eyes, Cuvier says, " some natu- 

 ralists attribute these organs to them," and De 

 Blamville has expressly described them. They are 

 two in number, placed on the back of the neck, 

 and, though excessively minute, appear to have a 

 very complete structure. 



Cuvier regarded the oars of this animal as its 

 aerating as well as locomotive organs, but the cor- 

 rectness of this opinion is denied by Eschricht ; in 

 fact we are not only in ignorance as to the laboratory 

 in which the circulating fluid undergoes its requi- 

 site purification, but also with respect to several 

 other details in the economy of this molkisk. 



The digestive apparatus is simple ; there is a 

 large liver ; and there are also long slender salivary 

 glands. 



The clio borealis, though not more than an inch 

 in length, forms the chief part of the food of the 

 huge Greenland whale, — and under the name of 

 " whales-food " is well known to the sailors who 

 chase this huge tenant of the ocean. The clio dwells 

 in shoals so countless and extensive that the surface 

 of the water for a vast distance often seems alive 

 with them, as they sport and gambol heedless of 

 their destroyer, who, as he passes through their 

 ranks, " thick as autumnal leaves in Valombrosa," 

 opens his mouth and ingulfs thousands at a snap. 



Sir E. Parry found the clio in astonishing abund- 

 ance in all parts of Baffin's Bay and Davis's Strait in 

 the neighbourhood of ice. Captain James Ross 

 observed it very numerous in most parts of the 

 Arctic Ocean, but less abundant in Regent's Inlet and 

 the Gulf of Boothia. Vi^hen the weather is calm 

 these animals come in myriads to the surface for 

 the purpose of respiration, but scarcely have they 

 reached it when they again precipitate themselves 

 towards the bottom. 



A, Clio borealis, yiew of the back ; a, the body ; 

 b, the viscera, seen through the common integul 

 ments ; c, the tubercles of the head, and the holes 

 wherein the three tentacula on each side are with- 

 drawn ; rf, rf, gills and fins. B, the same, view of 

 the belly ; a, c, d, indicate the same parts as in A ; 

 e, the two tentacula placed before the mouth. C, 

 the same laid open ; c, d, indicate the same parts as in 

 the two former figures; /,/, the external tunic or 

 skin ; g, g, the internal tunic or fleshy pannicle ; 

 h, h, the principal bundles of its fibres ; i, the mass 

 of viscera; m, the principal vein of the fins. 



We may pass from Clio to the Hyalseidae of 

 Cuvie- (family Thecosomata, order Aporobranchiata 

 of De Blainville). 



The general characters of this family may be 



summed up as follows : — Animal furnished with a 

 head, but it is not distinct ; a third natatory mem- 

 brane exists on the ventral region, it is small and 

 intermediate between the two large fins. The 

 mouth is situated in a cavity formed by the union 

 of the locomotive organs. Shell nearly always 

 present, but very variable in form. 



2587, 2588.— The Cymbulia 



(Ci/mbulia Peronii) . Cuvier describes the Cymbulia 

 as having a cartilaginous or gelatinous envelop in 

 the form of a boat or slipper, beset with pomts in 

 longitudinal rows ; and the animal itself as pos- 

 sessing two great wings which are at once branchiae 

 and fins, and between on the open side a third 

 smaller lobe which is three-pointed. See Fig. 

 2587; a, a, the fins; &, the intermediate lobe ; i, the 

 viscera seen through the shell. The mouth, pro- 

 vided with two small tentacula, is placed between 

 the wings towards the shut side of the cell, and 

 above are two small eyes. The transparency of the 

 texture permits the mternal organs to be distin- 

 guished with great facility. The shell is cartilagi- 

 nous, translucent, oblong, in the form of a slipper, and 

 entirely covered with a delicate and scarcely visible 

 membrane. M. Rang observes that this curious 

 and very incompletely known genus contains only 

 a single species (1829), which is found in the Me- 

 diterranean Sea ; and he adds that he only knows 

 it from a drawing communicated to him by Cuvier, 

 who in his ' R^gne Animal' remarks that in the figure 

 pven by M. de Blainville (' Malacologie ') the animal 

 IS placed in the shell the wrong way : and that his 

 (Cuvier's) description rests on recent and repeated 

 observations made by M. Laurillard. M. Deshayes 

 confirms this remark as to the inverse position of 

 the animal, and says that he has had occasion to 

 verify it often. M. Deshayes in his edition of 

 Lamarck (1836) enumerates five species. That 

 known to M. Rang was the C. Peronii. Fig. 2588 

 exhibits three figures of Cymbulia in three different 

 aspects : — a, the animal seen in the shell, seen from 

 above ; b, the shell edgeways ; c, the shell seen 

 from above. 



2589. — The Spibatella 



'Spiratella limacina, Blainville). Limacina arctica, 

 Cuv. ; Clio helicina, Phipps and Gmelin ; Argonauta 

 arctica, Fabricius. 



The spiratella is a curious little animal, the body 

 of which is elongated anteriorly, and turned into a 

 spiral form behind : branchiae in the form of plaits 

 on the back ; mouth furnished with two small ap- 

 pendages, which are united by one of their extremi- 

 ties to the anterior border. 



Shell very delicate, fragile, vitreous, spiral, not 

 carinated, turning rather obliquely on itself, with a 

 circular aperture and simple borders. (Rang.) 



Cuvier is of opinion that the Limacinae ought, 

 according to the description of Fabricius, to bear a 

 strong relationship to Pneumodermon ; but their 

 body is terminated by a tail, which is twisted spi- 

 rally (' contourn^e en spirale '), and is lodged in a 

 very delicate shell, of one whorl and a half, unbili- 

 cated on one side and flattened on the other. Cuvier 

 adds that the animal uses its shell as a boat and its 

 wings as oars when it would swim on the surface of 

 the sea. The same author remarks, that the only 

 species, Clio helicina of Phipps and Gmelin, is 

 scarcely less abundant in the Icy Sea than Clio 

 borealis [Clio], and is considered as one of the 

 principal aliments of the whale. He observes that 

 he does not know whether the animal figured by 

 Mr. Scoresby, of which M. de Blainville (' Malaco- 

 logie,' pi. xlviii. bis. f. 5) makes his genus Spiratella, 

 is in reality, as M. de Blainville believes, the same 

 animal with that of Phipps and Fabricius. M. 

 Rang considers Spiratella of De Blainville as syn- 

 onymous with Limacina, of which M. Rang states 

 that but one species is known, and says that it 

 would be interesting to have new accounts of it. 

 He speaks of its inhabiting the North Sea, its pro- 

 digious abundance, and the possibility of its serving 

 as food for the whales. Phipps mentions it as being 

 found in innumerable quantities in the Arctic Seas, 

 an(J describes its body as of the size of a pea, rolled 

 up into a spire like a helix, and its ovate, obtuse, 

 expanded wings as being greater than the body. 

 The cut is taken from the figure of M. de Blainville, 

 who founds his genus (which he places under his 

 family of Pteropoda, between Atlanta and Argo- 

 nauta) on the materials furnished by Mr. Scoresby, 

 and considers his Spiratella as synonymous with 

 Cuvier's Limacina. 



Mr. G. B. Sowerby figures a Limacina (in his 

 'Genera of Recent and Fossil Shells,' and in the 

 same number as that which contains Cymbulia) 

 from Messina. lie describes it as a thin, fragile, 

 spiral, discoid shell, umbilicated on both sides, and 

 carinated on the hack and below, with a membra- 

 naceous lamellar keel ; and he says that it has exter- 

 nally much the appearance of a very diminutive 

 umbilicated nautilus. 



"M. Deshayes, in his edition of Lamarck, remarks 

 that the Limacinse, of which M. de Blainville formed 

 his genus Spiratella, have in fact much analogy 

 with the Cleodorae ; and that they are Cleodorse 

 whose shell is spiral, and not swimming Gastropodk. 

 like the Carinariae and Atlantee. M. Deshayes goes 

 on to state he has many individuals preserved in 

 spirit, which he owes to the generosity of Dr. 

 r leming, that he has examined them with attention, 

 and that they have not the projecting foot of 

 Atlanta, nor a fin-like foot, but two lateral fins of , 

 the form of those of the Cleodorse. He adds tha 

 they have no tentacles, and no eyes, but a mouth il 

 the shape of a triangular slit at the summit of the' 

 angle which forms the fins. The shell is not closed 

 by an operculum, as that of Atlanta is. M. Deshayes 

 is of opinion that the genus ought to remain amonv 

 the Pteropods, where it was placed by Cuvier ano 

 Lamarck. 



2590. — The Three-spined HyaljEa 



{Hyalaa (rispinosa, Rang). In the genus Hyalgeit 

 the animal is globular or oblong, furnished with two 

 lateral expansions more or less elongated back* 

 wards ; the intermediate lobe of a semicircular 

 form ; two very short tentacles, hardly distinct, 

 contained in a cylindrical sheath ; the aperture of 

 the mouth provided with two labial appendages ; 

 branchiae pectinated, on each side, in a particular 

 cavity. 



Shell homy or vitreous, transparent, and fragile, 

 in form of a slipper, straight or recurved, with an 

 anterior opening, and split laterally, tricuspidated 

 backwards. (Rang.) 



M. Rang remarks that this beautiful and inter 

 esting genus, the anatomy of which has been made 

 known by M. Cuvier and M. de Blainville, is per- 

 fectly distinct from those which approach it. He 

 speaks of the Hyalaeae as very small animals, spread 

 over all the seas of the torrid zone, and a great part 

 of those of the temperate zones, and of the occur- 

 rence of the same species on the most opposite 

 points of the globe. He adds that the discovery 

 which he had made of many species, one in a fossil 

 state, had caused him to divide the Hyalaeae into 

 the two following groups : — 



1. Globtdosae. — Shell subglobular, having the 

 lateral slits nearly as long as itself, and the ap- 

 pendages placed very much backward. H. unci- 

 nata, &c. This group, he says, is the most nu- 

 merous. 



2. ElongatcB. — Shell elongated, having the lateral 

 slits short and the appendages advanced. H. tri- 

 spinosa, &c. 



Cuvier describes Hyalaca as having two great 

 wings, no tentacles, a mantle slit at the sides, 

 lodging the branchiae in the bottom of the fissures, 

 and covered by a shell equally slit at the sides, the 

 ventral surface of which is very convex, the dorsal 

 flat and longer than the other, and the transversal 

 line, which unites them behind, furnished with three 

 pointed dentilations. In the living state, the animal 

 projects by the lateral slits of the shell filaments 

 more or less long, which are productions of the 

 mantle. Cuvier concludes by observing that the 

 species most known (Anomia tridentata, Forskahl ; 

 Cavolina natans, Abildgaaidt; Hyalsea cornea (tri- 

 dentata), Lamarck) has a small yellowish demi- 

 transparent shell, which is found in the Mediterra- 

 nean Sea and in the ocean. 



M. de Blainville, who has published a monograph 

 of this genus in the ' Journal de Physique,' and in 

 the ' Dictionnaire des Sciences Natureiles,' states 

 that it contains already (1825) from five to six 

 species, all of which appear to be the inhabitants 

 of warm climates. He considers the genus Glan- 

 diolus of De Montfort as belonging to the Hyala'ae, 

 and quotes the observation of M. Defrance to that 

 effect with approbation. 



M. Deshayes enumerates sixteen recent species, 

 exclusive of Hyalaea cuspidata, which, he says, is 

 not a true Hyaloca, as Bosc, De Roissy, and Lamarck 

 believed, but a Cleodora. MM., Rang, D'Orbigny, 

 Lesueur, and Quoy and Gaimard, have principally 

 contributed to the number of species. 



Referring to Fig. 2.590,— « represents the fins; 

 h, the intermediate lobe ; c, the mouth ; e, the 

 lateral expansions of the mantle ; i, the viscera seen 

 through the shell ; h, the shell. 



2591. — The Tbidejjtatb Htal^a 

 (Hijalma tridentata of Forskahl and Gmelin); 

 Hyalaea papilionacea, Bory de St. Vincent ; Hyalia 

 cornea, De Roissy. 



This species inhabits the Mediterranean and the 

 warmer seas. Its size scarcely equals that of a 

 small hazel-nut. Referring to Fig. 2.591,— a re- 

 presents the anterior border of the animal, shovfing 

 the mouth. 



2592.— The Pybamidal Cleodoea 

 {Cleodora pyramidata). Cuvier remarks, that the 

 Cleodorae, for which Brown originally founded the 



