412 PISHES OF THE FIRTH OF FORTH. 



the nasal aperture along half its base, or nearly as far as 

 the posterior margin of the nasal valve ; the teeth in S. ca- 

 tulus are about double the size of those in S. canicula. 



The Large-spotted Dog-Fish, so named by Mr Y an ell 

 to distinguish it from the small-spotted species, is occasion- 

 ally taken on the coast of Devon in the trawl-net, but it 

 does not appear to be of so common occurrence as S. cani- 

 cula. In the Firth of Forth examples are occasionally 

 found in the salmon-nets at Queensferry. It is stated by 

 the fishermen, that it is more frequently met with on 

 some of the shores further north, and at Wick, specimens of 

 large size have been taken in the herring-nets ; but as the, 

 two species are so closely allied, it is not improbable that 

 they have been greatly confounded. I have seen examples 

 of both species of three feet and a half in length. They 

 feed on almost any animal substance, and extrude their 

 purses or eggs during the winter months. On dissecting a 

 specimen in the month of September, I found two purses of 

 large size, but the foetus was not in the slightest developed. 

 At one of the extremities of the horny capsule were attach- 

 ed two strong, slender tendrils, very much resembling that 

 which is used by fishermen under the name of Indian weed. 

 This and the last described species are said to produce 

 many young at a time. I have occasionally observed a va- 

 riety of this species, or probably the young, about a foot in 

 length, with the head, back, and sides, of a deep reddish- 

 brown, marked with a few large dark scattered spots. 



Genus LAMNA. — First dorsal fin in advance of the 

 ventrals ; anal fin present ; temporal orifices wanting ; the 

 branchial openings all before the pectorals. 



