1905.] NATURAL SCIENCES OF PHILADELPHIA. 475 



HOMALOPTERID^. 

 HOMALOPTERIN.E." 

 Ventrals separate, not united to form a disk. 



26. Homaloptera orthogoniata Vaillant. 



Head 5; depth 4|; D. iii, 8; A. iii, 6; P. v, 10, i; V. ii, 8; scales 

 63 in lateral line to base of caudal; 20 scales before dorsal; 11 scales 

 obliquely back from origin of dorsal to lateral line; 12 scales obliquely 

 forward from origin of ventral to lateral line, and same of anal ; width 

 of head H in its length; depth of head over eye 2^; snout If; width of 

 mouth 4; interorbital space 2^; first developed dorsal ray 1; first 

 developed anal ray If ; length of ventral 1 ; least depth of caudal 

 peduncle 2^. 



Body elongate, somewhat compressed, rounded in middle, lower or 

 ventral region of head and abdomen flattened, and trunk posteriorly 

 well compressed. Upper profile anterior to dorsal more or less evenly 

 convex. Greatest depth about origin of dorsal fin. Caudal peduncle 

 compressed, and its least depth about half its length. 



Head flattened below, more or less evenly convex above, and upper 

 profile nearly straight or only very shallowly convex. Snout long, tip 

 rounded and jiroduced well beyond mouth. Eye small, high, directed 

 rather laterally, near first f in length of head, and with free eyelid. 

 Mouth inferior, rather small, and lips thick and fleshy. Jaws rather 

 soft, especially upper. Lower lip formed into three thick fleshy folds. 

 A short thick conical cirrus at each corner of mouth, and 4 more along 

 front edge of snout just above upper lip. Tongue not distinct. Nos- 

 trils adjoining, frenum between narrow, posterior much the larger and 

 about in last third of length of snout. Interorbital space rather broad, 

 a little convex and greater than internasal space. 



Gill-opening lateral, not quite reaching forward till opposite pos- 

 terior margin of e^^e. Rakers short points, much shorter than fila- 

 ments, and not numerous. Isthmus broad, its width equal in length 

 to gill-opening. 



Scales rather small, especially those on lower costal region where they 

 crowd out and completely cover abdomen. Breast, head and fins, 

 except a few small scales on base of caudal, entirely naked. Scales 

 on post-ventral region large like those on side of body. Inner basal 

 regions of pectoral and ventral also naked. Lateral line of simple 



-' I have not consulted the original account of Homaloptera Van Hasselt. The 

 earliest one I have seen is in Bull. Sci. Nat. Geol. Paris, II, 1824, p. 377. I accept 

 the name in accordance with Bleeker's restriction of Homaloptera javanica Van 

 Hasselt as the type. 

 31 



