50 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



bel blackish; fins all blackish, the caudal nearly uniform ; the paired 

 fins darkest on the inner side. Sides with vertical series of mucous 

 pores, conspicuous in life. 



This species is not uncommon at Mazatlan, where several specimens 

 were obtained by Mr. Gilbert. Four specimens from Colima are also in 

 the National Museum. It was not observed at Panama. 



The original description of this species is brief and not entirely cor- 

 rect. That it was intended to refer to the species here described we 

 have ascertained by the examination of Dr. Gunther's original types in 

 the British Museum. 



SPECIMENS LN UNITED STATES NATIONAL MUSEUM. 



28140. Mazatlan. Gilbert. 



29284. Mazatlan. Gilbert. 



28289. Mazatlan. Gilbert. 



28290. Mazatlan. Gilbert. 

 29G47. Mazatlan. Gilbert. 

 8144 (4). Colima. John Xantus. 



16. Arius dowi (Gill) Giinther. 



Lcptariua doivii Gill, Proc. Ac. Nat. Sci. Pliila. 1863, 170 (Panama ; "generic" 



diagnoses and measurements). 

 Arius dovii Giinther, Fish. Centr. Amer. 1869, 476 (copied from Gill). 



Habitat. — Pacific coast of Central America; Panama. 



Head 4 (4f) ; depth G£ (7£) ; width of head 5£; length (29529) 10 inches. 

 D. I, 8 ; A. 4, 12. 



Body elongate, narrow and slender, the caudal peduncle If in head. 

 Head low and narrow, tapering anteriorly, the snout sub-truncate. Eye 

 small, 7 in head, placed rather high ; interorbital space little arched, 

 with ridges and depressions, 24 in head; snout 3| in head; breadth of 

 mouth 2^ in head. 



Mouth moderate, with thinnish lips; teeth villiform, blnntish; vom- 

 erine teeth forming two smallish, rounded patches, separated by a mod- 

 erate interspace ; each patch coniluent with the neighboring palatine 

 patch, which is rounded and rather large; the suture marked by a con- 

 striction. Palatine bands without backward prolongation. Premaxil- 

 lary band of teeth broad. 



Barbels very long; maxillary barbel extending well beyond tip of 

 pectoral fin ; outer mental barbel reaching well past front of pectoral ; 

 inner 2f in head. 



Ante-dorsal shield comparatively large, not distinctly crescent-shaped, 

 its divisions produced backward, their length about twice the length of 

 the shield on the median line; anterior margin with two cmarginations, 

 the point fitting into an emargination of the occipital process ; ante- 

 dorsal shield without keel. Occipital process very broad and short, its 

 edges nearly straight, its breadth at base considerably greater than its 

 length; its median line with a rather low keel. Foutanelle broad and 



