II. REPORTS ON THE EXPEDITION TO BRITISH 



GUIANA OF THE INDIANA UxNIVERSITY 



AND THE CARNEGIE MUSEUM, 1908. 



Report No. 2. 



A New Genus and Twelve New Species of Tetrago- 

 nopterid characins. 1 



By Marion Lee Durbin. 2 



Dermatocheir gen. nov. 



This genus differs from its nearest relative Hyphessobrycon in having 

 an archaic pectoral like Archicheir. The pectoral consists of a fleshy- 

 lobe, surrounded by a fringe of filaments. Inasmuch as the other 

 fins are well developed, and specimens of other species smaller than 

 the one described have the pectoral normal, the peculiarity cannot be 

 ascribed to extreme youth. It may of course be an abnormal speci- 

 men. 



Type, Dermatocheir caiablepta sp. nov. 



Dermatocheir catablepta sp. nov. 



Type unique, 18 mm. (No. 1198 Carnegie Museum Catalog 

 Fishes.) Tumatumari, above the falls. 



Head 3.5, depth 3.8 ; D. 11, A. 20 ; scales 5-33-3, eye 2.5 in the 

 head ; interorbitals very slightly greater than the eye, 2. 2 in the head. 



1 In the ditches, among weeds in canals and in the small woodland streams of the 

 lowlands of British Guiana occur large numbers of small Tetragonopterid characins 

 with an incomplete lateral line. That no attention has been paid to these fishes by 

 previous collectors is shown by the fact that out of a total of sixteen species, thirteen 

 are new, and the other three had not been recorded from the Guianas. The genera 

 with an incomplete lateral line had until recently been united with the conglomerate 

 genus Tetragonopterus . They are closely allied to Astyanax and Mcenkhausia. The 

 species of Pristella have teeth along* the entire edge of the maxillary. The new 

 species of this genus is described in No. I of these reports. Dermatocheir has an 

 archaic pectoral fin and may be an abnormal specimen. Hemigrammus has a scaled 

 caudal and Hyphessobrycon has the caudal naked, characters of ijut little significance. 



C. H. Eigenmann. 



2 Contributions from the Zoological Laboratory of Indiana University, No. 102. 



55 



