THE DOGFISHES AND THEIR ALLIES 2905 



long. Nothing more was heard of the species until January, 1878, in which year 

 the capture of another specimen was reported from the Peruvian coast near Callao; 

 finally, in the " nineties " it was discovered on the west coast of Ceylon, where two 

 or three specimens were obtained. One of these was presented to the British 

 Museum; and, having been mounted, is now exhibited in the Fish Gallery, where 

 it forms one of the most striking objects, although only a young example, measuring 

 seventeen feet from the end of the snout to the extremity of the tail. It has been 

 stated that this fish feeds on seaweeds, but it is more probable that its food is 

 similar to that of the basking shark. 



THE DOGFISHES AND THEIR ALLIES Family SCTLLIIDJE 



Agreeing with the preceding families in the absence of spines to the dorsal fin, 

 the dogfishes and their allies may be distinguished from the shark hitherto 

 noticed, in which the mouth is inferior in position, by the more backward situation 

 of the first dorsal, which is placed above or behind the line of the pelvic fins. 

 They have no nictitating membrane to the eye; and the teeth are small, with 

 several series generally in use at the same time. In all there are distinct spira- 

 cles. 



Represented in British waters by the- larger (Scy Ilium canicula), 

 and lesser spotted dogfish (S. catulus}, this genus is characterized by 

 the first dorsal fin being above or behind the line of the pelvic pair; by the origin 

 of the anal being in advance of the line of that of the second dorsal; the absence 

 of serration of the upper edge of the caudal fin; and the small and delicate teeth, 

 which are arranged in numerous series, and generally have a long central cusp, 

 flanked by one or two small ones on each side. About half a score of species have 

 been described, ranging over the coast regions of most temperate and tropical spe- 

 cies, and all of comparatively small size; the majority having prettily spotted skins. 

 Their food consists mainly of crustaceans and mollusks; and their flesh is eaten not 

 unfrequently by fishermen, while in the Orkneys, where the British species are more 

 abundant than elsewhere, it is regularly dried for winter consumption. The sha- 

 green of their skins is also employed in wood polishing. These sharks lay eggs of 

 the form shown in our illustration. Fossil dogfishes date from the period of the 

 Chalk; and they are represented in the Kimeridge Clay by the extinct Pal&oscyllium, 

 in which the origin of the second dorsal fin is placed in advance of that of the small 

 anal. 



Among several allied genera we may especially notice the zebar 

 shark {Stegostoma tigrinum} of the Indian Ocean, attaining a length 

 of from ten to fifteen feet, and noticeable for its handsome coloration, which con- 

 sists of a brownish-yellow ground color, marked with black or brown transverse 

 bars or round spots. In this fish the first dorsal fin is above the line of the pelvic 

 pair, while the second is in advance of the line of the anal, which is approximated 

 to the caudal; the latter being greatly elongated, and equal to half the total 

 length. Young specimens of this shark are generally met with near the coast, but 



