284 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.39. 



tion must be determined by the basal end of the basal joint, even 

 though that joint be fused with the ventral surface of the head for its 

 entire length. 



In the mature adult the second joint is usually called basal, but 

 the proximal end of this joint is distinctly posterior to the other 

 mouth-parts. Heller and Bassett-Smith both represent this correctly 

 in their figures, but evidently failed to see its significance. 



2. Their development: If we examine a half-grown female we 

 find that these maxillipeds are really three-jointed, made up of two 

 basal joints and a terminal claw. (See pi. 54, fig. 159.) In the 

 mature female, carrying fully developed egg-strings, of the new 

 species, Bomoloclius eminens, both basal joints are still distinctly 

 visible. (See pi. 53, fig. 151.) 



Even the proximal end of the second joint, therefore, is not the true 

 base of the appendage, but this is still farther back and directly 

 behind the second maxillae, in a position corresponding exactly to 

 that in the male. To be sure, the appendage is turned outward instead 

 of inward, and the second joint is turned forward outside of the other 

 mouth-parts. But there can be no question that the basal joint is 

 posterior to the second maxilla, and therefore this must be the 

 maxilliped. 



3. The analogy presented by the genera Anchistrotos Brian 

 {Eucanthus Claus) and Tseniacanthus Sumpf. In each of these genera 

 both pairs of maxillae and the maxillipeds are present and in their nor- 

 mal position in the female as well as in the male. In Anchistrotos the 

 second joint is free, but in Tseniacanthus it is fused solidly to the head. 



Moreover, in the latter genus it is almost the exact counterpart 

 of that found in the Bomolochinse, a large triangular second joint and 

 a terminal claw curved into an S-shape, but tipped with setae. The 

 similarity in shape and structure is sufficient to establish the identity 

 of the appendages. In these two genera, therefore, they are unques- 

 tionably maxillipeds, and hence must be so regarded in the Bomo- 

 lochinse. 



4. The analogy presented by the appendages of the male: This 

 sex was discovered by Claus for the genus Bomolochus in 1864, and 

 was found to possess large and powerful three-jointed maxillipeds, 

 which were normally placed behind the other mouth-parts. The 

 structure and position of these organs in the male are so typical that 

 no one would think of calling them anything but maxillipeds. But 

 when we come to examine them we find that their basal joints are 

 attached considerably outside the other mouth-parts, in a position 

 corresponding to that of the proximal end of the second joint of the 

 same appendages in the female. 



