TRIAKIS SEMIFASCIATA. 165 



Triakis. 



Triakis Muller & Henle, 1838, Charlesworth's mag., 2, p. 36; 1841, Plagios., p. 63. 



Head depressed, flattened beneath, snout blunt. Anterior nasal valve with 

 a rounded lobe. Eye with a nictitating fold. Spiracles small, behind the eyes. 

 Mouth arched, labial folds and labial cartilages well developed. Teeth small, 

 numerous, bases two-rooted, each tooth with a stronger median cusp and at 

 each side of its base a denticle or denticles. Hindmost gill clefts above the 

 pectorals. First dorsal above the space between the pectorals and the ventrals. 

 Second dorsal above the anal. Caudal short, no pit at its origin, a notch behind 

 the subcaudal; subcaudal lobe small. 



Median cusp of teeth acuminate, lateral cusps sharp 



greyish with cross bands and large alternating spots of brown 



semifasciata (page 165) 

 brown with cross bands of darker and with scattered spots of black 



scyllium (page 166) 

 Median cusp of teeth short, broad-based, lateral cusps short 



slaty brown with scattered small spots of black , maculata (page 167) 

 greyish brown, uniform henlei (page 168) 



Triakis semifasciata. 



Plate 50, fig. 5, 11, 12. 



Triakis californica Gray, 1851, Chondropterygii, p. 56 (name only). 



Triakis semifasciatum Girard, 1854, Proc. Acad. nat. sci. Phil., p. 196; 1858, Rept. Pacif. R. R. Fish, 

 p. 362; Dumeril, 1865, Elasm., p. 398; Gunth., 1870, Cat. fishes Brit, mus., 8, p. 384; Jordan & 

 Gilbert, 1882, Bull. 16, U. S. nat. mus., p. 20; Jord. & Everm., 1896, Bull. 47, U. S.nat. mus., p. 31. 



Trunk elongate, compressed; head rather narrow, depressed, flattened 

 beneath, crown little convex; snout rounded in front and on the edges. Nos- 

 trils nearer to the mouth than to the end of the snout; anterior valve with a 

 somewhat produced rounded lobe above which there is an internal bilobed fold, 

 the partition. Ej^es small, with a nictitating fold, Plate 50, f . 5. Spiracles small, 

 distant behind the eye less than half the length of the orbit. Mouth in a low 

 arch; labial folds extending about half the length of the jaw, above and below. 

 Teeth very small, numerous; median cusp strong, oblique, with one or more 

 smaller ones, denticles, at each side of its base. Largest gill opening about the 

 length of the orbit, liindmost small, above the pectorals. Pectorals short, subtri- 

 angular^ two thirds as wide as long, angles rounded, hind margin nearly straight, 



