A.MPIIIPOBA — STEBBING. 615 



two sexes are in close agreement, except in regard to the second 

 gnatbopods. These are much larger in the male, with the palm 

 of the sixth joint less oblique, and defined by a decided tooth, the 

 palm between this and the finger hinge being crenulate with a 

 cavity in the middle. The border of the cavity on the hinge 

 side rises to a little tooth, from which tlie crenulation is continued 

 without slope. The stout finger impinges against the palmar 

 tooth, and has a minute prominence on its inner border, touching 

 the tip of the hind border of the pahnar cavity. 



The fourth and fifth peraeopods are stouter in the male than in 

 the female. In both sexes the telson has a minute point at 

 the centre of the apical border. 



I have already called attention to the similarity of the second 

 gnathopod in the male of Ahera incequipes and the female of 

 Elasmopoides chevreuxi. The present .species offers another 

 instance of the same singular resemblance, the hand and finger of 

 the male being so like in structure to those found in the different 

 sexes of the other two species, that one might readil}- accept them 

 as all belonging to a single species, did not otlier considerations 

 foi'bid it. They pertain in fact to three distinct genera. As 

 already mentioned, the specimen of Mcera inceqnipes in the 

 present collection has a true pair of second gnathopods, both 

 members of the pair being equally developed, as if to flout the 

 specific name. But the male of Euryslheus tJiomsoni in the 

 "Thetis" collection has only one member of this pair finely 

 -developed, the other being less developed than in the female, the 

 hand forming a narrow oval with no well-marked palm. The 

 same inequality of the second gnathopods is noted by Pro- 

 fessor Haswell in Mmra crassipes, which I have ventured to 

 transfer to the present genus. If my classification of it is right, 

 it stands very near to the present species, being chiefly distin- 

 <yuished from it by the different structure of the second 

 gnathopods. 



It will no doubt be remembered that, where the second 

 gnathopods attain to considerable bulk, it is not uncommon to 

 find a great disparity between the two members of a pair. 



Localities. — Botany Bay, 50-52 fathoms. An imperfect speci- 

 men, a female, was obtained off Wata Mooli at 5i-59 fathoms 

 depth. 



Family AMPITHOID^. 



Ampithoidce, Stebbing, Das Tierreich, xxi., 1906, pp. 631, 738. 

 Amphithoidce, Chevreux, Mem. Soc. Zool. Fr., xx., 1908, p. 515. 

 Amphithoidre, Walker, Trans. Linn. Soc, xii., 1909, pp. 326, 3il. 



