THE DOG-FISH. 



Fig. 48. 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.) 



A, base of skull. BB, basi-brancliial. BC 1 , BC 5, first and fifth cerato- 

 branchials. BE 1 , BE 5, first and fifth cpi-branehials. BH 1 , first hypo-branchial - 

 represented as though seen through the cerato-hyal. BH 2, second hypo- 

 branchial. BP 1 , BP 5, first and fused fourth and fifth pharyngo-branchials. 

 E, upper jaw. EB 1, EB 2, EB 3, first, 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- 

 byal. HC, cerato-hyal. MM, hyo-mandibular cartilage. L 1, L 2, labial 

 cartilages. N, nasal cartilage. NC. olfactory capsule. R, median bar of 

 rostrum. R|_, lateral bar of rostrum. S, notch for Cuvierian sinus. T, 

 foramen for neck of Thyroid gland. 



