366 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxiii. 



the present genus. But if so, it is a distinct species and is not a 

 synonym of any of the known species. 



Milne Edwards claimed to have both sexes, but the specimen he 

 has figured as a male (PI. VIII, figs. 2 and 3) was certainly a 

 female without egg-strings. He says nothing about its size. If it 

 were not fully developed some of the discrepancies, and possibly all, 

 might be explained, for no development stage of any species of this 

 genus has ever been seen. 



In view of these facts, we are warranted in omitting the species for 

 the present and awaiting further evidence. 



ECHTHROGALEUS BRACCATUS Dana. 



Dinematura braccata Dana, 1852, p. 1370, pi. xcv, fig. 4. 

 Echthrogalcus {Nogagus) braccatus Heller, 1865, p. 197, pi. xx, fig. 3. 

 Nogagus braccatus Bassett-Smith, 1899, pp. 460, 464. 



Dana, who first described this species in 1852, referred it to the 

 genus Dinematura, but Steenstrup and Liitken in 1861 created anew 

 genus Echthrogaleus out of several of the Dinematura species, 

 including this one of Dana. Heller in 1865 described a Nogaus 

 form as the male of this species, and Thomson recorded in 1889 the 

 capture of the species at Auckland, New Zealand. Finally Bassett- 

 Smith in 1899 made the species a synonym of Echthrogaleus affi.nis. 

 After a careful examination of the evidence the present author can 

 not agree with Bassett-Smith. Dana plainly states as his reasons 

 for distinguishing the species from affinis the difference in the shape 

 of the lateral plates on the second thorax segment, the size and posi- 

 tion of the anal laminae, the relative size of the carapace and genital 

 segment, and the size and shape of the third thorax segment. In 

 Dana's species also the posterior sinus of the genital segment is 

 very deep and the rudimentary sixth segment plate is not visible, 

 while in affinis the sinus is much shallower and the sixth segment 

 plate is visible at its enlarged base. 



These reasons are sufficient to separate the two species when sup- 

 ported by such authorities as Steenstrup and Liitken and Heller. 



Wlien we come to compare Dana's species with coleoptratus, how- 

 ever, the evidence is not as conclusive; still there are enough differ- 

 ences to prevent us from declaring the two species synonymous on 

 present evidence. These differences are found in the shape of each 

 of the three pairs of dorsal plates on the thorax segments, in the 

 fact that the third pair of plates have no transparent dots in Dana's 

 species, while these are very prominent in coleoiJtratus , and in the 

 relative size of the carapace and genital segment. Dana's species 

 was without egg-strings; 'and if it was a young female, not fully 

 matured, some, if not all, of these differences could be readily 

 explained. But Dana gives the length as half an inch, which is 

 larger than an adult coleoptratus. 



