OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 297 



Genus Nematocarcinus, A. Milne-Edwards. 



1881. Nematocarcinus, A. Milne-Edwards, Ann. Sci. Nat. "Zoo!.," ser. 6, vol. xi. art. 4, p. 14. 



1882. Eumiersia, S. I. Smith, Bull. Mus. Comp. Zool. Harvard, vol. x. p. 77. 

 1884. Nematocarcinus, S. I. Smith, U.S. Fish. Comm.for 1882, p. 368. 



1888. „ Bate, Rep. Voy. " Challenger," vol. xxiv. pp. lxxxvi, 800. 



1901. ,, Alcock, Gatal. Indian Deep-Sea Macrura, p. 86. 



1906. „ Rathbun, U.S. Fish. Comm.for 1903, part iii. p. 926. 



In this widely distributed genus the names of species are numerous, embracing 

 N. cursor, A. Milne-Edwards, 1881 ; Eumiersia ensifera, S. I. Smith, 1882; fifteen 

 names given by Bate in 1888 ; and N. agassizii, Faxon, 1893. In 1901 Alcock 

 suo-o-ests that Bate's productus, tenuipes, and intermedius may be all the same 

 species, and all not improbably synonymous with the N. ensifer of S. I. Smith, to 

 which Kemp further refers Bate's Stochasmus exilis as at most a variety, Calman 

 and Hansen having already shown that the problematic Stochasmus was founded 

 on the young of Nematocarcinus. Alcock questions also the validity of Bate's 

 N. undulatipes, supposing that it may be a synonym of N. cursor, to which he 

 definitely assigns Bate's N. paucidentatus as a variety. The relative size and 

 armature of the rostrum, to which Bate has attached so much importance in dis- 

 tinguishing his species, are of doubtful value for that purpose, as they vary with the 

 age of the specimen and are otherwise inconstant. There is the further inconveni- 

 ence that the long pointed rostrum, like the enormously long perseopods and the 

 tapering telson, is peculiarly liable to be damaged. The close resemblance among 

 all the accepted species makes it probable that the mouth-organs are practically 

 alike in all. But in regard to these it is important to follow the excellent account 

 and figures given by S. I. Smith in 1882, rather than those of Bate. In 1893 I 

 accepted Bate's statement that the palp of the mandibles was two-jointed, neglecting 

 Smith's earlier and correct evidence that it is three-jointed. Smith also shows that 

 the second maxillipeds are seven- (not six-) jointed, since the dactylus, which Bate 

 overlooks, " is articulated obliquely along the distal end of the propodus." This 

 feature, in which the dactylus has quite ceased to be dactyliform, helps to link the 

 present genus with several others in the tribe Caridea. Smith has noted that in 

 the first maxillipeds the last of the three terminal joints of the endopod is very 

 minute. It is indeed difficult to distinguish, but the two preceding are rather long. 

 Bate's figure consolidates all three into a tolerably short single joint. According to 

 Smith's description of the first maxillae of N. ensifer, " the endognath is much shorter 

 than the distal lobe of the protognath, and truncated at the extremity, which is 

 armed with a stout seta either side and a third one just below the tip." In our 

 specimens these maxillae correspond with Smith's description and figure, except that 

 the " palp" or terminal joint which he calls the endognath has at the inner corner of 

 its truncate apex a long and strong, distally feathered spine, and at the outer corner 

 a much slenderer and shorter spine, and on the surface below the apex a raised 



