166 THE PLAGIOSTOMIA. 



fin applied to the side reaching below the middle of the dorsal. Dorsal moderate, 

 origin little forward of the hind margin of the pectoral, upper angles rounded, 

 produced extremity reaching a vertical from the ventrals. Vent near the middle 

 of the total length, second dorsal more than half as large as the first, similar in 

 shape, equal in base. Anal less than half as large as the second dorsal, origin 

 below the middle of the base of the second dorsal, base reaching behind that of 

 the dorsal about one length of the orbit. Caudal less than one fourth of the total 

 length; subcaudal fin followed by a notch, lobe very small. 



Light brownish or greyish, lighter yellowish or whitish below; back with 

 about a dozen transverse bands of brown each about as wide as the internarial 

 space, separated by spaces of equal or greater width, below which are large alter- 

 nating spots of brown. In cases there are narrow streaks of brown bisecting the 

 spaces, and, on the lower parts of the sides of the body, some smaller spots. 

 There is a large spot above the base of the pectoral and there are small ones 

 scattered over the head and the caudal fins. The color is most often lighter in 

 the centres of spots and bands. 



California to Mexico. 



Triakis scyllium. 



Tn'a/assc(/Miu»iMuLLER&HENLE, 1841, Plagios., p. 63, pi. 26; Dumeril, 1865, Elasm., p. 397; Gunth., 

 , 1870, Cat. fishes Brit, mus., 8, p. 384; Ishikawa & Matsuuha, 1897, Cat. fishes, p. 62; Jord. Ik 

 Snyder, 1900, Proc. U. S. nat. mus., 23, p. 336; Jord. & Fowler, 1903, Proc. U. S. nat. mus., 26, 

 p. 609; Pietschmann, 1908, Sitzb. Akad. wiss. Wien, 117, p. 689. 



Trunk elongate, subtriangular in cross section, with a low ridge above the 

 vertebrae. Head depressed, flat beneath, broader than high, crown little convex. 

 Snout short, rounded, blunt, length nearly equal to width of mouth. Nostrils 

 nearer to the mouth than to the end of the snout ; anterior valve wide, broadly 

 rounded, with an internal fold and pointed lobe above it. Mouth in a low arch, 

 nearly three times as wide as long; labial folds wide and thick, almost half the 

 length of each jaw, lower shorter. Teeth small, numerous, closely set, oblique, 

 each with a denticle or two denticles at each side of the long acuminate median 

 cusp. Length of orbit greater than the width of the hindmost gill opening, less 

 than half the preoral length of the snout. Spiracle small, behind the eye a half 

 length of the orbit. Pectoral large, width more than two thirds of the length, 

 inner angle rounded, outer blunted, fin applied to the side subtending half the 

 base of the dorsal. Dorsal origin above the hind margin of the pectoral, length 

 of base more than half its distance from the second dorsal, hinder angle reaching 

 a vertical from the ventrals. Second dorsal little smaller than the first, origin 



