CIIONDROPTERYGII BRANCHIIS LIBERIS. 



33 1 



regular. The first (tarsal, containing a strong spine, is placed over the pectorals ; and the males, as in 

 the Sharks, have a bony appendage to the ventrals ; hut these are divided into three branches, and they 

 have spinous appendages hefore the base of the ventrals, and small spines on the point of a fleshy 

 appendage between the eyes. Their eggs are large and flattened, with a leathery covering, and 

 having margins. [In fact, with some singular peculiarities, they approach pretty closely to the G 

 with fixed gills.] 



C. motutrosa, the Kin? of the Herrings, and Cat of the Mediterranean, is three feet Ion?, and of a silvery 

 colour spotted with brown. It inhabits t he European seas, the northerly ones mosl abundantly. Another, forming, 

 perhaps, a second subgenus, OaUirkynchut, has the snout ending in a fleshy appendage like a toe. The 

 second dorsal begins oyer the ventrals, and terminates at the commencement of the tin under the tad. Only 

 one species, from the South Seas, is known. 



THE SECOND ORDER OF CIIONDROPTERYGII. 



CIIOXPROITKRYGII BRAXCHIIS FIXIS. 



These have their gills attached at the outer edge, with a separate opening, through which 

 the water from each gill escapes. They have also small arches of cartilage suspended iu their 

 muscles, opposite the gills, which may be called gill-rihs. They form two families. 



THE FIRST FAMILY OF THE CIIONDROPTERYGII BRANCHIIS FIXIS,— 



Selachii (the Sharks and Rays), — 

 Which has been comprised in two genera, has many common characters. The palatals and postmandi- 

 hularies are alone armed with teeth, supplying the place of jaws, the usual bones of winch are mere 

 rudiments, a single hone representing the tympanal, jugal, and temporal hones, and the preopercuhim. 

 The os liyoidei is attached to this pedicle, and supports gill-rays as in ordinary fishes, although not 

 distinctly visible externally. It is followed by branchial arches, but has none of the three pieces which 

 compose the gill-lid. They have pectorals and ventrals, the latter behind the abdomen on each side of 

 the vent. Their membranous labyrinth is inclosed in the cartilage of the cranium, and their cavities 

 contain starchy masses and not -tony ones. The pancreas is a conglomerate gland, and not divided 

 into cceca ; the intestinal canal is short, but with a spiral valve. The sexes pair regularly, the females 

 having oviducts highly organized, which supply the place of a matrix in those that bring both their 

 young alive ; such as produce eggs have them with a horny covering, the substance of which is Bupplied 

 by a larger gland surrounding the oviduct. The males are easilj known by large appendages on the 

 inner edge of the ventrals, the use of which is not well known, [though believed to serve as elaspert]. 

 Squahu, the Sharks properly so called, have a long body; a thick, ilt-1 1 \ tail; mod rate pectorals; 

 and resemble ordinary fishes in their form, having the gill-openings on the sides of the neck, not 

 below, as in the Rays, and the eyes in the sides of the head. The snout is supported by three carti- 

 laginous branches arising from the fore part of the cranium, and the rudiments of mamillaries, inter- 

 maxillaries, and premandibulars, may be traced in the skeleton. The bone of the shoulder is sus- 

 pended in the muscles behind the gills, without connexion with the cranium or the spinal column. 



Some are viviparous ; others produce eggs covered with yellow and transparent horn, of an obi 



shape, and w ii b cords of born at the angles. Their small gill-ribs are apparent, and small ones arc 



traceable along the spine; their flesh is dry and leathery, ami eaten only by the poor. They are 

 numerous, and form many subgenera. 



ilium (called Dog Sines on the British coast). — Snout blunt and short ; nostrils near the mouth, continued In 



ove i" the edge of the lip, and more or lees i lose i by membranes ■. teetb with a long point in the middle, and 



a shorter one at They all have spiracles, and one anal Sn; the dorsals are far backward, the first being 



even before the ventrals ; their caudal >> long and truncated, and thro gill-openings under the p i the 



British ones j the anal i- againsl the Interval between the two dorsal . The ipeciei are i 



.s'. eanicula, the Small Bpotted Dog-fish, with numerous spots an I thi 1.—S, rutin*, ti | 



spotted Dog-fish, with th . sometimes ocellated, and the ventrals iquare. — /I. meUutemmm, Black- 



