42 



while in the female they measure about two-thirds of it, are filiform and the longest of all, 

 projecting by one-half to three-fourths their carpus beyond the antennal scales; in the male 

 the coxa is strongly dilated at the inner side and its anterior margin bears a lamelliform 

 process with truncate or obtuse tip and slightly turned outward; in the female the coxa is 

 not dilated, but it carries at its antero-internal angle a small, sharp tooth, somewhat larger 

 than that which exists on the coxa of the 4"^ pair, but with no tubercle behind it. The carpus, 

 sometimes (in some males) distinctly shorter than the merus, in other specimens barely shorter or 

 of equal length, appears, in the male, 3-times, in the female 3Y3-times as long as the two last 

 joints taken together and the dactylus is a little more than half as long as the propodus. 



In the male the sternum carries, between the legs of the 3'''^ pair, a tubercle that is 

 sharply carinate and compressed medially like a forwardly directed tooth and a similar larger 

 tubercle between the legs of the 4* pair is produced into a strongly compressed, lamelliform 

 tooth, the pointed tip of which is also directed forward; between the legs of the 5"^ pair the 

 median carina is low and obtuse, in younger males sharp and in still younger ones it rises 

 into a compressed carinate tooth that is directed forward and that is smaller than the tooth on 

 the preceding somite. 



Each of the two branches of the petasma is folded longitudinally iii two folds of which 

 the anterior is much narrower distally than the posterior; the tooth-like process on the inner 

 border of the basal joint is rounded. The sternum of the i^' abdominal somite bears between 

 the base of the pleopods a transverse, compressed tubercle, that is carinate posteriorly in the 

 middle, the carina that is strongly compressed, being rounded. A smaller acute tooth exists 

 between the pleopods of the 2""^ pair and a still smaller one between those of the 3'''^; all 

 these teeth are in the female smaller than in the male. 



In the female the posterior margin of the penultimate thoracic sternum is prominent 

 and overhangs the sternum of the last somite; the sternum of the penultimate somite bears a 

 strongly compressed tooth or process that reaches to the dilated coxae of the 3'''^ pereiopods. 

 The sterna of the three preceding somites are also carinate in the middle and the median 

 crest of the 3''^ somite forms posteriorly an obtuse tooth. The sternum of the posterior segment 

 rises into a tubercle rounded both transversely and longitudinally; this tubercle appears sometimes 

 obscurely carinate longitudinally and usually occupies the whole interspace between the ^^^ legs. 

 When this is not the case, the tubercle appears quadrangular, a little broader than long or 

 sometimes longer than broad; sometimes it appears rhomboid, the two anterior sides making 

 a right angle with one another and separated by grooves from the rest of the sternum. The 

 branchial formula is the following: 



The branchial formula differs from that given by Bouvier as characteristic of this genus 



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