1870.] 



561 



[Cope. 



Hemigkammus robustulus. Cope. 



Radii D. 10, A. 27; scales 7 — 35 — 6. Form deep compressed; length 

 without cavidal 2.25 times depth, and 3.5 times length of head. Profile 

 straight, steeply descending to the obtuse muzzle. Interorbital width 

 greater than diameter of orbit ; eye one-third of head. Five stout but 

 small teeth on the maxillary bone, which latter reaches to the line of the 

 middle of the pupil, hence the gape pf the open mouth is greater than in 

 some other species. The dorsal fin is not so elevated as in some species 

 of Tetragonopterus, and originates behind the line of the ventrals. The 

 greatest elevation of the dorsal line is in advance of its origin. Sub- 

 orbital bone large ; mandible longer than muzzle. 



Muzzle black ; cheeks black punctate ; body brown, a greenish lateral 

 band with indistinct humeral and caudal spots. Middle of caudal fin 

 blackish. Total length .051 M. ; to origin ventrals .018 M. ; to origin of 

 anal .025 M. 



This little Chaxacin I refer to the genus Hemigrammus of Gill,* because 



* Ann, Lye. New York, 1858. 



the lateral line is only half developed, extending in the present species to 

 beneath the middle of the dorsal fin. The general form and dentition are 

 stout. The gill rakers are elongate on the inferior, but sparse and short 

 on the superior limb of the hyoid arches. 



From Pebas, Equador. Numerous specimens from Hauxwell's col- 

 lection. 



Myletes lippincottiakus. Cope. 



Radii D. 16, A. 39 ; lateral line 80. Depth of body two-thirds length 

 without caudal ; thus the foi-m is discoid. Muzzle 

 very obtuse ; mandible longer. Orbit one-third 

 of head, and 1.5 times into very convex inter- 

 orbital region. Thirty-two ventral spines. Adi- 

 pose fin two-thirds the length of the rayed dor- 

 sal; caudal with a very narrow sinus-like emargi- 

 nation above the middle of the edge. Ventrals 

 not reaching vent, commencing a little in advance 

 of the line of the first dorsal ray. 



Color yellow silvery ; dorsal region with steel 

 reflections ; a dusky spot above the middle of the 

 pectoral on the lateral line. 



The teeth of the external premaxillary series 

 are very small, and in close contact witii those of 

 the second. 



Length .112 M. to line of origin of anal .057 ; 

 depth .068 ; do. of head at orbit .022 M. 



From Para, Brazil, J. C. Brevoort's collection. 



Dedicated to my friend, James S. Lippincott, author of important con- 

 tributions to Meteorology, Agriculture and other subjects. 



A. p. S. — VOL. XI— 43e 



