240 BULLETIN 201, UNITED STATES NATIONAL MUSEUM 



tor, 7 males, 16 females ; Pontadora, Perl as Islands, 8 to 10 fathoms, 

 January 28, 1916, 2 females. 



Distribution. — Puget Sound (Walker) ; San Pedro, Calif. 

 (Holmes) ; west coast of Panama. 



Remarks. — Walker (1898) described H. odontops from Puget Sound 

 and Holmes (1900) E. spinosus from California. These two sup- 

 posedly distinct species are obviously very closely allied. The only 

 character that Holmes points out as distinguishing his species from 

 Walker's is that the latter has the inner margin of the antennal scale 

 devoid of setae, whereas in the California species the scale is setose 

 all around. I cannot believe that this is a real difference. Walker 

 makes no mention of this special character in his description. On 

 the other hand, Holmes gives no description of the eye, nor does he 

 make any mention of spines on the inner uropods of his species, char- 

 acters which could have been compared with those given by Walker 

 as specific to E. odontops. The two forms agree in such fundamental 

 characters as the telson, the endopods of the third thoracic limbs, 

 and the number of articulations in the sixth joint of the endopods of 

 the succeeding limbs. Both Walker's and Holmes' descriptions are 

 inadequate, and it is difficult to decide whether the two species are 

 really distinct. 



The specimens here recorded are from the Pacific coast of the 

 Panama region. They agree substantially with both Walker's and 

 Holmes' species, yet they present certain differences which are best 

 given in tabular form. 



Table 8. — Principal differences between the present Panama specimens of 

 Heteromysis odontops and spinosus and those previously described 



The Panama specimens agree with both H. odontops and H. spinosus 

 in having the lateral margins of the telson armed with 20 to 24 spines, 

 which extend along the entire margin, and also in that the apical 



