1908.] NATURAL SCIENCES OF PHILADELPHIA. 57 



apex forming nearly over its posterior basal margin, and a long slender 

 point projecting behind equal in length to width of mouth. Origin of 

 second dorsal a little nearer posterior basal margin of first dorsal than 

 origin of upper lobe of caudal, base of fin hke that of first dorsal well 

 elevated and fleshy, and fin otherwise similar with posterior point 

 about equal to eye horizontally. Caudal long and slender, origin of 

 upper lobe begins a little behind that of lower, and its distal expansion 

 about 3^ in its own length. Lower caudal lobe a little elevated below, 

 and length of its base about 1^ in entire length of upper. Anal inserted 

 a little behind middle of base of second dorsal, or a little nearer origin 

 of lower caudal lobe than tip of depressed ventral, and similar to second 

 dorsal, only smaller, posterior point equal to horizontal eye-diameter. 

 Pectoral large, upper margin rather evenly convex, reaching f to origin 

 of ventral, and its posterior margin slightly concave. Ventral inserted 

 about midway between origin of ventral and that of anal, rather 

 broad, and its lower margin a little concave. Clasper small, about 

 half length of posterior point. 



Color in alcohol dull uniform gray-brown above, merging into grayish- 

 white tint uniformly over lower surface of body. Upper fins like back 

 or with grayish, both pectoral and ventral paler below. Iris pale 

 brassy and pupil slaty. 



Length about 26 inches. 



No. 617, A. N. S. P., cotype of M. equeslris Bonaparte. Italy 

 (Bonaparte, No. 248). From Dr. T. B. Wilson. 



Also Nos. 618 to 620, with same data. They show: Head 5^ to 6^; 

 depth 8^ to 10|- ; width of head If to If in its length ; snout 2 to 2J ; eye 

 4^ to 6^; width of mouth 3f to 3^; interorbital space 2^ to 2|; front 

 edge of first dorsal 1| to If; front edge of anal 1| to 2f ; pectoral 1 to 

 If ; length 10^ to 21f inches. The smallest example is uniform on the 

 back, like the larger ones, and is without any spots or markings. My 

 confusion of these examples with Galeorhinus galeus^ was due to the 

 original labels being evidently wrongly placed. I have verified this 

 by an examination of Bonaparte's original catalogue, where they are 

 also wrongly entered in the latter's own handwriting. 



Mustelus mento Cope. Fig. 1. 



(Proc. Am. Philos Soc. Phila., XVII, 1877, p. 47, Pacific Ocean at Pecasmayo, 

 Peru.) 



Head about 5; depth 7f ; width of head If in its length; snout 2^; 



eye 5J; width of mouth 3f; interorbital space 2f ; front margin of 



8 Proc. Acad. Nat. Sci. Phila., 1901, p. 332, PI. 13, fig. 4 (anatomy). 



