PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 459 



tndinal ridges, which rise higher than the temporal ridges; this entire 

 region nearly or quite destitute of scales [in T. exilis the middle of the 

 top of the cranium is scarcely elevated and without longitudinal ridges, 

 the whole region being more or less closely scaled} 5 scales of frontal 

 regiou extending little forward of base of premaxillaries (in T. exilis, 

 exteuding for more thau one-fourth the length of the prenuixillaries.) 

 Cheeks well scaled ; scales on opercle very minute. 



Scales not very small, green. 



Dorsal tin beginning and ending behind anal, its origin above base 

 of fifth anal ray; anterior rays of both fins produced; median and pos- 

 terior rays equal, the latter not reaching nearly to base of caudal ; anal 

 lobe higher than dorsal lobe, its height four-fifths length of i)Ostorbital 

 part of head. Yeutrals small, extending about one-third the distance 

 to origin of anal, their insertion midway between base of median caudal 

 rays and middle of cheeks. Pectorals broad, as long as postorbital part 

 of head, the upper ray broad. Caudal lunate, the lower lobe the longer; 

 the middle rays not quite twice as long as eye. 



Head 21 in length; depth nearly 18. D. 1, 10: A. 1, 17; P. 13; Lat. 1. 

 ca. 250. 



Color; green above ; white below; a dusky dorsal stripe; a silvery 

 lateral stripe; sides of head silvery; upper part of cheeks punctulate; 

 body and fins without dark points; a blackish half bar between cheeks 

 and opercles ; a blackish blotch above eye and one in front of nostrils. 

 Fins olivaceous, all more or less dusky at tij). Posterior x^ortion of pec- 

 torals abruptly black. 



This species is abundant at Mazatlan, where it is one of the common 

 market fishes. It reaches a length of about two feet, and it is known to 

 the Mexican fishermen as ";8'ierWte." 



It resembles its Californian representative, Tylosurus exilis, very 

 closely, difl'ering in several details, some of which are noticed above. 

 The two species may be distinguished at sight by the color of the pec- 

 torals, which are, in T. exilis, plain olivaceous. The dorsal and anal 

 lobes in the latter species are not dusky at tip. 



2. Tylosunis fodiator, sp. nov. (-28190, 283-2'?.) 



A spe*^ies of large size, remarkable for the great strength of its jaws. 



Body robust, subterete, as broad as deep ; caudal peduncle slightly 

 compressed, as deep or deeper than broad, the lateral line forming a 

 low black cutaneous fold along its length. 



Head very broad and strong, the cheeks nearly vertical. Interorbital 

 space very broad, two-thirds length of postorbital part of head. Mid- 

 dle of top of head with a broad, shallow, nearly scaleless, longitudinal 

 groove; sides of top of head obli(]ue]y striated and rugose, forming a 

 prominent ridge above the eye; distance between nostrils greater than 

 usual, more than one- sixth length of snout. 



Jaws comparatively short, tapering, very stiff and not fragile; lower 



