1888.] PRECEEDINGS OF UNITED STATES NATIONAL MUSEUM. 411 



LIST OF FISHES NOW IN THE U. S. NATIONAL MUSEUM, COL- 

 LECTED IN NICARAGUA BY DR. LOUIS F. H. BIRT. 



BY DAVID STARR JORDAN. 



A small collection of fishes has been made in Nicaragua by Dr. Louis 

 F. H. Birt. These were sent to the U. S. National Museum, wbere they 

 were received December 11, 1SS8. Of these specimens those numbered 

 from 39907 to 39912 are said to be from (Lake ?) Nicaragua; the others 

 (39913 to 39920) from a point 40 miles above the mouth of the Kio Sau 

 Juan, which is the outlet of Lake Nicaragua. This would be about 

 half-way'between the lake and Grey town, at the mouth of the river. 



39907, 39908. Ailurichthys filamentosus (Svrainson). (Felichthys filamentosus 



Swainsou; Gahichthys blochi Cuv. & Val.) 



This species greatly resembles Ailurichthys marinus, with which it 

 has hitherto been usually confounded. It is probable that the latter is 

 chiefly or wholly confined to the coast of the United States, and the 

 tropical representatives of the species belong to the present type, for 

 which filamentosus is the oldest specific name. 



The chief difference is in the much greater development of the occip- 

 ital process or buckler in A. filamentosus as compared with A. marinus. 

 The anal rays in our specimens of A. marinus are 23; in A. filamentosus, 

 26; shield on top of head much more extensively rough than in A. 

 marinus, the granulations extending on each side of the foutanelle to 

 before it; granulated area before occipital process broader than long, 

 its width more than half head; occipital process triangular, emarginate 

 behind, its width at base about 1| in its length and highly granular; 

 basal bone of dorsal spine short, but extending down for a considerable 

 distance saddlewise, its prolongations visible through the skin. (In A. 

 marinus the occipital process is small and oblong, of nearly the same 

 width behind as before.) Dorsal spine a little shorter than head, little 

 longer than pectoral spine; dorsal filament reaching to or beyond adi- 

 pose fin; pectoral filament to just beyond front of anal; maxillary bar- 

 bels to end of pectoral spine; color of A. marinus. 



39909. Chalcinopsis dentex Giinther. 

 A large specimen. 



39910, 39911. Rhamdia guatemalensis (Glinther). 



These specimens agree fairly well with Giinther's account, except that 

 the tip of the anal does not reach nearly to the end of the adipose fin, 

 when laid backward. One has 12 anal rays, the other 13. 

 39912. Heros motaguensis Giinther. 



Two specimens ; no distinct dark spot on subopercle ; otherwise agree- 

 ing fairly with descriptions. 



