234 



ICHTHYOLOGY. 



Chondrop- allied to Sq.c€ntrina,\)wt has conspicuous, ovate, hard, ca- 

 terygii. rinated scales. 



belaehii. -j-j^g gj^jj,^ jjj^g jji^^ pj- jjjQgt other sharks, is rough, with 

 ''"^"^ numerous sharp granular eminences. 



ScYMNUs, Cuv. This subdivision has all the charac- 

 teristics of Centrina, except the dorsal spines. 



The European species is the Sq. Americaniis of Brous- 

 sonet and Shaw. It occurs on the coasts of France, off 

 Cape Breton, which lias been mistaken for the transatlan- 

 tic Cape Breton. It appears to be identical with Risso's 

 Sq. Nicensis. 



The formidable animal described by O. Fabricius, in his 

 Fauna Groenlandica, as Sq. carcharias, is now, from the 

 descriptions of Scoresby and others, to be referred to this 

 sub-genus. It is Scoresby 's Sq. borealis. It wants the 

 anal fin, but has the temporal orifices. It grows to the 

 length of twelve or fourteen feet, and is six or eight in 

 circumference. Scoresby mentions the singular appen- 

 dages which he invariably found attached to the cornea of 

 this animal. Some have supposed them to be parasitic 

 animals. If so, it is singular that they should be so uni- 

 formly in the same position, and of the same size, about 

 one or two inches long, and cleft at their fore extremity 

 into two parts. This shark is peculiarly attracted by a 

 dead whale, out of which it scoops at once masses of 

 blubber as large as a man's head. The sailors believe 

 this species to be blind, from its returning to feed on its fa- 

 vourite morsel, even after having aflensingkniferun through 

 its body ; but this only shows its fondness for whale 

 blubber, — to which circumstance we may also attribute the 

 comparative safety of Greenland sailors who have fallen 

 into the water when flensing the whale. But, if we may 

 credit Fabricius, when this delectable food is not present, 

 he will attack the slender bark of the Greenlanders. 



To this division belong also the Sq. spinosus and La- 

 bordii. 



Genus Zyg^na, Cuv. This genus, which has the ge- 

 neral form of body and fins of Carcharias, is distinguished 

 by the extraordinary form of its head, that has no analogy 

 in nature, except in some of the insect tribe. It is flat- 

 tened horizontall}', truncated in front, and extended late- 

 rally into two arms, at the extremity of which are the 

 eyes, giving to the animal the form of a hammer. The 

 mouth is below the centre of this singular head, and the 

 nostrils at its anterior edges on each side. The most com- 

 mon in Europe is the .S'^'. zygcena, or hammer-headed 

 shark, which often attains the length of sixteen or seven- 

 teen feet, and is formidable on account of its voracity 

 and strength. It is found also around the West Indies, 

 and in the Indian Ocean, especially at Taheite, where the 

 natives are said, from their dexterity in swimming, to hold 

 it in little dread. It is a very prolific animal. Two kin- 

 dred species are known : the Sq. Blochii, Cuv., which dif- 

 fers in having the nostrils nearer the middle of the head, 

 and its two dorsals much nearer the tail ; and Sq. tiburo, 

 or heart-headed shark, a much rarer species, which we 

 have received from the coast of Guyana. We here figure 

 ZygcEna Leivinii, a species captured off the south coast of 

 New Holland. Plate CCCVII. fig. 5. 



Genus Suuatina, Dumer. ; Angel-fish. Has the tem- 

 poral apertures without the anal fin ; but its mouth is ter- 

 minal, and its eyes are both placed on its dorsal surface, in 

 which it differs from all the sharks. The head and body 

 are flattened ; the pectoral fins are extremely broad, and 

 project forward to the sides of the head, but are separat- 

 ed from it and the neck by a fissure, in which the bran- 

 chial apertures are placed ; the two dorsals are behind the 

 ventrals, and the tail is equally finned above and below the 

 spinal column. 



The best-known species is the Sq. squatina, Linn., or 

 angel-shark, which grows to eight or ten feet. It is a bold 



and voracious fish ; when captured, it bites with great Chondrojv 

 fury ; it preys much on flat fish ; it has tentacula on its terygii. 

 upper lip ; its eyes, placed obliquely, give it a sinister look- Sela chiL 

 The English name has been given ironically to this hide- 

 ous creature, which is by seamen generally termed devil- 

 fish. 



The teeth are slender, sharp, and dilated at their base ; 

 the dorsal fins very small, the pectorals very broad, the 

 ventral large, and enclosing the male organs. The upper 

 lobe of the tail longer than the lower. It is very prolific, 

 fourteen young being sometimes found in its belly ; twelve 

 frequently. 



To this genus we raust also refer the Sq^ aculeatus of 

 the Mediterranean. 



Genus Pristis, Lath. ; Saw-fish. This last genus has 

 the general form of the Squali, but is more flattened in 

 front, and has the branchial apertures beneath, like the 

 Rays. The most peculiar character, however, consists in 

 the great depression and extension of the snout, which 

 has on each side a row of strong teeth or spines, which 

 are trenchant on the fore-side, and mucronated. These 

 spines are not, however, their true teeth. These are 

 lodged in the mouth, and are very small and rounded. 

 But, with their formidable beak, they are said successfully 

 to attack the larger Cetacea. In the foetal Pristis the ru- 

 diments of these osseous spines are mere tubercles, and 

 the snout is folded up over the head of the embryon. 

 These spines are not, like the teeth of cartilaginous fishes, 

 attached by ligaments to the bones, but are firmly implant- 

 ed in the bone of the snout. 



The best-known species is the Sq. pristis of Linn, or 

 Pristis antiqiiorum. It grows to a great size. We have 

 measured snouts more than ten inches in diameter, and 

 four feet seven inches in length, with sixteen or eighteen 

 spines on each side, some of which projected three inches. 

 The animal attains the length of sixteen or eighteen feet. 

 There are other species chiefly distinguished by the num- 

 ber and form of these spines : as Pristis cuspidatus, — Pr. 

 pectinatus, with numerous slender teeth, — Pr. microdon, 

 — P. cirratus, with alternate long and short teeth, — and 

 Pr. semi-sagittatus, a small Indian species, in which the 

 spines are deeply denticulated on the posterior edge. 



Genus Raia (or Ray) of Linnaeus. This great genus of 

 the Selachii is very numerous, and the species often grow to 

 a vast size. They are readily recognised by their flattened 

 body, like the Pleuronectes, forming a horizontal disk, very 

 broad in proportion to its thickness, in consequence ofthe 

 body graduating into the enormous pectorals of the ani- 

 mal, which unite in front with the snout, and extend on 

 both sides of the abdomen to the base of the ventral 

 fins. See skeleton of the thorn-back (i?. clavata), Plate 

 CCCVII. fig. 9. The scapula of these vast pectorals are 

 articulated with the spine just behind the branchial aper- 

 tures. These apertures, the nostrils, and mouth, are on 

 the ventral surface of the fish ; the temporal orifices, and 

 the eyes, are on the dorsal surface. The dorsal fins are 

 usually placed on the tail. These animals are oviparous. 

 Their eggs are coriaceous, square, with long angles. The 

 subdivisions of Cuvier are the following. 



Genus Rhinobatus, Sch. Distinguished by the length 

 of the snout ; connects the sharks and rays. They have a 

 thick and fleshy tail, like Squali, with two dorsal and two 

 caudal fins. Their snout and pectorals form a sharp rhom- 

 boid. Their teeth are placed in a quincunx arrangement. 

 In some the first dorsal is placed over the ventral fins, in 

 others it is placed farther back. The best known is the 

 IVIediterranean Raia rhinobatus, which is found four feet 

 in length. The others are, R. T/iouiniana (Plate CCCVII. 

 fig. 7), supposed by Cuvier a variety of that just named, 

 but it has such difference of form as to entitle it to be con- 

 sidered a distinct species ; R. djiddensis, Forsk. ; one de- 



