KOUSSETTES. 



llol 



dorsal margin as from the ventral, but on the tail at 

 about the middle of the sides, until it reaches the an- 

 terior |),irt (if the caudal fin, where it bends down- 

 wards ill a loop to the lower third of the depth of 

 the l)ody. 



The Black-mouthed Dog-fish is most known in the 

 Mediterranean and on the coasts of Portugal and Nor- 

 way, this being probably due to the circumstances that 

 it generally lives at a depth of about 100 — 250 fthms., 

 and that fisheries at this depth are most developed in 

 the said localities. But it also roves into higher strata, 

 being met with, though seldom, in the North Sea, and 

 penetrating in the Skager Hack and Cattegat into 40 



fathoms of wafer (Malm) off Bohusliln and in Christia- 

 nia Fjord, or even, as once happened, in March, 1847, 

 according to Nilsson, into the Sound off Kk-k. Lowe 

 has described it from Madeira; according to Collett 

 it has been fmind off Trumsu. It thus lias a wide 

 geographical range in the North Atlantic. 



The food of the Black-mouthed Dog-fish consists 

 of fish and crustaceans. It takes the ordinary bait of 

 deep-sea lines. During spring and summer the female 

 deposits iier singular eggs (fig. 333), two at a time, 

 as described bj- Gunnerus. The life of this species is 

 otherwise little known; but where it is taken in any 

 number, the Hcsh is considci-ed eatable. 



Genls SCYLLIORHINUS '. 



Nostrils approximated behind to the mouth or even meetin(] the anterior margin of the nipper Jaiv, the distance 

 hetneen tvhirh margin and the tip of the snout is less than the postorhitaJ length of the head. Upper edge of 



the caudal fin without prominent serrations. 



As lias been hinted above, the difference from the 

 jirecediug genus is rather inconsiderable. The most 

 important distinction consists in the advancement of the 

 mouth and the more or less marked prolongation of the 

 nosti'ils back towards the mouth cavity. Consequently 

 we also find in the genus Scglliorhinns that the tip of 

 the lower jaw is in a line with or even in front of the 

 ])reorbital margin. The genus is indeed without seri-a- 

 tions at the upper edge of the caudal fin, though these 

 may sometimes be traced in the difference between the 

 large s])iny scales in the upper rows on each side and 

 tlie smaller and smoother ones in the median dorsal 

 line at the said spot; but it has a compensation for 

 tiiem in the stronger development of the spiny scales 

 on each side of the body aliove and behind the anal 

 fin, which almost exactly resemble jaw-teeth.. These 

 scales literally form a rasp, which the fish uses as a 

 defensive weapon. 



To the characteristics of the genus also belongs 

 the form of the egg-capsules (fig. 33.5). These are 

 similar to those of the Rays, oblong, rectangular, and 

 flattened, hut with one half thicker than the other. 

 .Vt each corner they are furnished witli a long (mea- 

 suring sometimes half a metre) filamentous appendage. 

 When the first pair of these tendrils emerge from the 



cloaca, the female coils them round a branch of sea- 

 weed or coral, where the egg is left hanging. Two 

 eggs, as a rule, become simultaneously ripe for exclu- 

 sion, one in each uterus; and the female deposits them 



i'ig. 335. Egg of Nurse Hound (Sci/lliorliiniis stellaris), cut open to 

 sliow tliC enclosed foetus, and willi the posterior (the first excluded) 

 cnid turned downwards. Nat. size. After Moreau, who further states 

 tliat tlic ova of this species differ from those of the Rough Hound 

 in tliat the thickened side-margins are transversely striped. 



° 2y.i).lov in Aristotle, elsewhere av.ikaE (lanicula in Gaza), = irhelp. 



.'!crindimn-iaii Fishes. 



