1886.] PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 341 



Head 3^ in length; depth 5 in head; breadth at pectorals 9 J in head. 

 D. I., 16; A. 1,19. Scales iibout 225; 150 series before dorsal. Length 

 of specimen measured (from Venice) 17 inches. 



Body rather slender, distinctly compressed, more so than in any of the 

 species of Tylosurus proper, but much less so than in Tylosurus Mans; 

 caudal peduncle rather slender and long, compressed, everywhere deeper 

 than broad, and without trace of keel of any sort. 



Jaws slender and long, the upper jaw from eye contained 5 times in 

 length of body, and 2 times length of rest of head. Mouth not capable 

 of being completely closed, there being a slight arch at base of upper 

 jaw. Eye rather small, 1^ in interorbital width, 2^ in post orbital part 

 of head, and 6f in snout. 



Upper jaw shorter and somewhat slenderer than lower, the jaws more 

 unequal than in Tylosurus. 



Teeth rather small, slender and close-set, those in upper jaw consid- 

 erably larger than those in the lower, the latter most numerous; the 

 small teeth outside of these little conspicuous. Vomer with a small 

 patch of villiform teeth in most specimens, this occasionally little de 

 veloped or obsolete {acus Eisso). Bones and scales somewhat green. 



Maxillary chiefly concealed by the preorbital. 



Head strongly compressed, broader above than below. 



Top of head less uneven than in the species of Tylosurus, rather nar- 

 row, and transversely convex, with a rather broad and very shallow 

 median depression, which is scaly for its entire length. Superciliary 

 and temporal ridges little promiueut, scarcely striate. Two slight folds 

 across edge of preopercle. 



Cheeks with rather large deciduous scales, arranged in about? rows; 

 opercle with similar scales. Scales on body rather large, but very thin 

 and deciduous. 



Gill-rakers slender and rather numerous ; about 18 developed, the 

 longest not quite as long as pupil. 



Dorsal fin of moderate length and height, the posterior rays low, the 

 anterior lobe If in postorbital part of head. 



Anal higher than dorsal and inserted considerably farther forward. 

 Caudal fin moderately forked, the lower lobe little longer than the upper, 

 one-fourth longer than postorbital part of head. 



Pectorals short and broad, 1^ in postorbital part of head. Ventrals 

 small, H in postorbital part of head, their insertion unusually far back, 

 midway between axil of pectoral and base of caudal. 



Color greenish above, sides and lower i>arts silvery ; a very obscure 

 silvery lateral streak; a dark streak along middle of back, a dusky spot 

 on supercilium ; no black bar on opercle. Fins mostly pale. 



