410 FISHES OF THE FIRTH OF FORTH. 



SCYLL1UM CATULUS.* THE L.ARGE-SPOTTED DoG-FlSH. 



Specific Characters. — Valves of the nostrils separate; not reaching 

 to the mouth. 



Description. — From a female specimen one foot eight inches in 

 length. Anterior part of the body rounded ; belly somewhat flatten- 

 ed; caudal extremity compressed, greatest thickness behind the 

 pectorals, tapering from the ventrals ; from the point of the snout 

 to the third gill-opening on the neck, exactly one-sixth of the en- 

 tire length, and one-fourth as far as the middle of the space be- 

 tween the two dorsals ; first gill-opening is placed mid- way between 

 the point of the snout and the end of the pectoral fin. Colour of 

 the head, back, and sides, reddish-grey, spotted with dark brown ; 

 belly, under surface of the pectoral and ventral fins, dirty white; behind 

 the ,fins spotted. Snout blunt, rounded, and slightly depressed, pro- 

 jecting beyond the upper jaw; nostrils rather large, elongated, placed 

 beneath, much nearer the point of the snout than to the anterior part 

 of the orbit, and immediately in front of the upper lip ; the inner half 

 concealed by a prolongation of skin so as to form a sort of valve ; 

 each valve is somewhat of a triangular form, rather short, not reach- 

 ing to the upper jaw, having a lobe underneath of a similar form, but 

 somewhat smaller. Mouth large, the angle of which extending back 

 as far as in a line with the middle of the orbit ; under jaw shortest ; 

 teeth small and sharp pointed, placed in three or more rows in each 

 jaw; each tooth is furnished with a small denticulation on each side 

 of its base. Eyes moderate, of an oblong-oval ; branchial openings 

 five, arranged in a longitudinal series on each side of the neck, the 

 first the largest, rather more than equalling the length of the orbit, 

 the last the smallest, about half the size of the first, the fourth placed 

 immediately over the anterior extremity of the base of the pectoral 

 fin. Behind and a little under the posterior angle of the orbit, is si- 

 tuated a small temporal orifice communicating with the mouth ; skin 

 rough, allowing the hand to be passed from head to tail, but not in 

 the opposite direction, owing to the scales being strongly denticulat- 

 ed, with the points directed towards the caudal extremity ; the tip of 

 the snout perfectly smooth. First dorsal fin somewhat of a triangu- 

 lar form, rather less than equalling its height, situated over the mid- 

 dle of the space between the ventral and anal fins, and mid- way be- 

 tween the third branchial opening and the end of the tail ; its ante- 

 rior margin oblique, the posterior vertical. Second dorsal about the 



* Scyllium calulus, Yarr., Cuv. Squalus stellaris, Jen. Rock Dog-Fish, 

 Bounce. 



