THE FISHES OF ALASKA. 



225 



Family i. HEPTATREMIDyE. The Borers, or Hagfishes. 



1. Polistotrema deani Evermann & Goldsborough, new sjiecies. 



Head to first gill-opening G.5 in total length; depth 13.6; tail 7; branchial distance 7.3; gill-open- 

 ings 11 or 12; teeth 11 + 11 and 10 + 10; base of tongue under third gOl-opening. 



Body long and slender, little compressed; head somewhat depressed; nostrU broad, slit-like, termi- 

 nal; mouth a longitudinal slit with wrinkled edges; 8 barbels, 4 above and 4 below; apparently no ante- 

 rior rudimentary gill-slits. Fin-fold well pronounced on ventral surface of body, gi'adually disappear- 

 ing in front of middle of length; caudal rounded, showing ray-like marks. 



Color purpliiih-blue or that of the Santa Clara prune, becoming blacker in alcohol, and uniform over 

 the whole body; ventral fold or anal fin not bordered by white; no white border about gill-openings. 



This species differs fi'ora Polistotrema stouli in a ninnber of important respects, chief of which are 

 the much shorter head (6.5 instead of 4.5 in body), the longer tail (7 instead of 8), the more numerous 



Fig. 1. — Polistotrema deani Evermann & Goldsborough, new species. Type. 



teeth, and the color. In P. stouti the ground color of fresh specimens" was brown plus a little pink, 

 which changes to a bluish tint in preserved specimens; ventral fold or anal fin bordered by white, which 

 often encircles the caudal fin; gill-openings bordered by white ring; old examples often mottled or 

 blotched about the head with white; a few specimens had in addition 1 or 2 l)lack blotches on the side 

 uf the body. 



In the following table are given certain comparative measirrements of 97 examples of P. stouti,a and 

 con-esponding measurements of our 4 specimens of P. deani. All measurements, etc., were taken from 

 the right side of fresh hags that had just died. The specimens were laid flat on a board, but none was 

 stretched. In two of the specimens of P. deani the left side was used, as being more satisfactory. All 

 measurements are in millimeters, from which proportional measurements can be readily computed. 



a From Monterey Bay and examined for us by Mr. William F. .\Ilen. at the Hopkins Seaside Laboratorj-. 



B. B. F. 1906—15 



