420 FISHES OF THE FIRTH OF FORTH. 



cies of shark have been confounded by naturalists under 

 the name of Squalus maximus. 



Genus SPIN AX. — First dorsal fin in advance of the 

 ventrals ; anal fin wanting ; temporal orifices present ; 

 branchial openings all before the pectorals ; a sharp, strong 

 spine in front of each of the dorsals. 



Spinax acanthias.* — The Picked Dog-Fish. 



Description. — From a specimen eighteen inches in length. Body- 

 fusiform ; nose long ; head depressed. Colour of the back and 

 sides, slate-grey ; under part dull white, in young specimens the 

 back is spotted with white, and the caudal lobe is often margined 

 with pale yellow. First dorsal fin somewhat of a quadrangular 

 form, terminating behind in a projecting point, directed towards the 

 caudal extremity ; the height in front more than equalling the length 

 of the base ; situated about one-third of the whole length from the 

 point of the nose. Second dorsal fin smaller than the first, and an- 

 swering to it in shape ; placed about mid- way between it and the end 

 of the caudal lobe ; in front of both dorsals is a strong, sharp spine, 

 the one behind being much the longer of the two. Caudal lobe 

 rounded at the end ; the lower lobe triangular and rather larger than 

 the second dorsal ; ventrals approaching to a quadrangular, situated 

 under the middle of the space between the two dorsals. Pectorals 

 of a triangular form, rather larger than the first dorsal, concave be- 

 hind, slightly rounded on the upper margin. Nostrils small, placed 

 beneath, about half-way between the tip of the snout and the upper 

 jaw, partly covered by a minute membranous flap ; branchial open- 

 ings five on each side of the neck, all before the pectorals. Under 

 jaw shortest; teeth small, not denticulated, placed in two or three 

 rows in each jaw, their points directed towards the angle of the 

 snout, very sharp and cutting ; a large temporal orifice situated a 

 little behind the posterior angle of each orbit ; lateral line tolerably 

 defined ; skin rough when the hand is passed from tail to head, but 

 of a granulated feel in the opposite direction. 



The Dog-Fish is a well-known species of Shark, and is 

 common on almost every part of the British coast, more 

 especially on that of Cornwall, where as many as twenty 



* Spinax acanthias, Cuv., Yarr. Squalus acanthias, Jen., Linn. Bone- 

 dog, Hoe, Orkney, Dog-fish. 





