50 PEOCEELtlXGS OF UNITED STATES NATIOXAL MUSEUM. [1885. 



youug iudividiuils may be found still retaining these appendages. Lilt- 

 ken observes tliat E. georgianus Cuv, & Val. should " have its place be- 

 side E. evolans and E. ohtusirostris, but it differs in this respect, that it 

 is provided with barbels; it is even a question if the examples which 

 have lost these could be distinguished from the species above-named." 



As none of the specimens of E. georgianus examined by Dr. Liitkeu 

 «xceed 2f inches in length, we regard thorn, in view of what we already 

 know of the loss of these appendages in furcattts and mesogaster, as, 

 without much doubt, young individuals of evolans. 



The ^'- monociirus''^ of Eichardson is, according to Liitken, undoubt- 

 edly identical with E. georgianus. 



The color of very young specimens of evolans, less than 1^ inches in 

 length, is bluish above, silvery below. There is a brownish band across 

 the body at base of caudal fin ; a second band around body covers pos- 

 terior half of dorsal and tins ; some black on ventrals and on posterior 

 half of pectorals. 



In a larger specimen there are no bands on the body, the ventrals are 

 •white and the pectorals mostly dark. The length of the pectoral bears 

 about the same proportion to the length of the body in both old and 

 young specimens. The same is true of the proportionate length of the 

 first and second rays of this tin. 



Specimens of f inch to 9 inches in length are in the museum of the 

 Philadelphia Academy. These are from the Atlantic and Indian Oceans, 

 the Bahamas, the Sandwich Islands, and from Chili. We have exam- 

 ined others from Korth Carolina and the West Indies. 



Genus IV.— EXOCCETUS. 

 Exoccetus. 



ExoccETUS, Artedi, Genera Pisciuiii, 6, 1738 {volitans). 

 Exoccetus, Linnaeus, Systema Naturae, ed. x, 1758,310 (volitans). 

 Cypselurus, Swaineou, Class'n Fishes, etc., ii, 1839,296 (nultaUi). 



This group includes most of the species of flying-fishes. Its species 

 are in general larger in size than those of the other groups, and their 

 wing-like paired fins are more extensively developed. As already stated, 

 we regard Cypselurus as unworthy of consideration as a genus, the 

 barbels being in most cases, and probably in all, characteristic of young 

 fishes. 



ANALYSIS OF SPECIES OF EXOCCETUS.* 



a. Anal tin long, its base a little less thau that of the dorsal, its first ray nearly op- 

 posite first ray of dorsal; rays of anal 11 to 12. 

 b. Second ray of pectoral simple (as well as the first ) ; third ray divided ; fourtli 

 and fifth rays longest . 



• We here omit (No. 12) E. cyanopterus and its doubtful synonym, E. albidactylus, the 

 ^lescriptions of both being incomplete. 



