224 



THE DOG-FISH. 



Fig. 46. -Scyllium canicula. The skull and visceral skeleton seen from 

 the ventral surface. The labial: cartilages, extra-branchials, and 

 gill-rays of the left side have been removed, (a. m. m.) 



Ai IJiise of sknll. BB, basi-braucliial. BC 1, BC 5) fii'st aud fifth cerato- 

 brancbials. BE 1, BB 5, first aud fifth epi-branchials. BH 1, first hypo- 

 branchial, represented as tliough seen througli the cerato-hyal. BS 2, second 

 liypo-brauchial. BP 1, BP 5, first and fused fourth aud fifth i)haTyiigo- 

 branchials. E, upper jaw. BB 1,EB 2, BB 3, firsb, second, and third extra- 

 branchials. EL, ligament connecting the two halves of the upper jaw. F, 

 lower jaw. !FL, ligament connecting the two halves of the lower jaw. G-, 

 gill-ray. HB, basi-hyal. HO, cerato-hyal. SM, hyo-manflibiUar cartilage. 

 Xj 1, Xi 2, labial cartilages. M", uasal cartilage. ITC, olfactory capsule. R, 

 median bar of rostrum. BL, lateral bar of rostrum. S, notch for Cuvierian 

 sinus. 



