280 PROCEEDINGS OF THE ACADEMY OF 



CORYDORAS SEMISCUTATUS, Cope, sp. nov. 



Radii D. I. 11, L, no adipose portion ; A. I. 6 ; Y. 6 ; P. I. 10. 

 Scuta 23 above, including postcephalic, no azygus shields. Pre- 

 orbital bone and shield single, large, extending half way from 

 orbit to maxillary, and downwards, .4 way to line of mandible. 

 Postcoracoid processes wide, with convex inner margins which 

 are separated by a wide fissure, the surface striate rugose, no 

 lateral shield separates them from the base of the ventral fins. 



Profile steep, arched in front of nares; muzzle contracted, 

 pointed. Orbit 3.5 times in head, 1.66 times in muzzle and inter- 

 orbital space. Head 2.8 in length without caudal fin ; depth 2.4 

 times in same. Inferior lip beaded on margin, which easil}' 

 separates, forming a loop ; no median barbels visible. 



General color above pearl}^ or nacreous-blue, with metallic re- 

 flections on postclavicle and operculum. 



This species shows a marked tendency to the genus Brochis in 

 the increased extent of the osseous shields of the thorax and 

 sides of the head. The enlarged number of dorsal fin raj's is an- 

 other indication of such affinity. It represents very closely, I 

 have no doubt, a young stage of Brochis coeruleus in the incom-- 

 pleteness of the shield development, and might, by some, be re- 

 garded as that animal itself. Specimens of the latter of nearly 

 the same size betray no approach to it in characters, and experi- 

 ence elsewhere warrants the opinion that the parallelism will be 

 seen at a far younger age than any of our specimens represent. 



CORYDORAS PALEATTJS, Jen. 

 CallicMhys paUattis, Jenyns Voyage BeagJe Fishes, p. 113. Giintlier, 

 Catal. B. M. v. 230. 



CORYDORAS AMBIACUS, Cope, sp. nov. 



Form stout, compressed, dorsal line arched, front convex at 

 oi'bit, slightly concave on the elongate muzzle. End of muzzle a 

 little projecting beyond mouth, its outline gradually expanding 

 to orbit. Interorbital region transversely convex. Lower lip 

 widel}^ reverted, its marginal barbels each shorter than the dia- 

 meter of the eye. Latter 3.33 times in length of head, 1.75 times 

 into muzzle and interorbital width. Length of head 3.2 times in 

 length without caudal fin, and 1.25 in depth of body. 



Lateral shields 22-21 ; azygus shields one basal and one flat. 



[Februarj- 13, 



