DECAPOD CRUSTACEA FROM MADAGASCAR. 919 



although not more so than in some specimens of Series A. The 

 epigasti-ic and postorbital crests are somewhat indefinite; in some 

 specimens they are nearly in line, but in others they are separated 

 by a distance estimated at 2/5ths of that between the epigastric 

 and the frontal margin. The exorbital tooth is not prominent 

 and the epibranchial is smalL 



The specimens of this series approach the P. hmnhloli and 

 P. grandidieri of Miss Rathbun's monograph, especially perhaps 

 the latter, although they do not agree exactly with the description 

 of either. They diifer so much among tlaemselves ia all the 

 characters that might be used to distinguish them from the 

 specimens of Series A, that I cannot regard them as specifically 

 distinct ; from Series B they are more easily defined. 



Series D. — In the two specimens of this series the carapace is 

 very smooth, the rugosities on the anterior part of the branchial 

 region being hardly perceptible. The general antero-posterior 

 convexity of the carapace is well marked, the vai'ious regions are 

 also convex, and the grooves between them correspondingly 

 distinct. The most characteristic feature is the inflation of the 

 anterior branchial regions, which, in both, but especially in the 

 female, is much more marked than in any of the specimens men- 

 tioned above. The antero-lateral marginal line is not prominent 

 and its granulations are nearly obsolete. In the female the 

 distance between epigastric and postorbital crests is nearly half 

 that between the former and the front, while in the male the 

 proportion is not more than two-fifths. 



These specimens, which I caimot believe to be specifically 

 distinct from the smoother specimens of Series A, approach 

 P. goudoti in general aspect, and are separated from it chiefly by 

 the character of the epigastric crests, which do not project nearly 

 so far forwards, are much less oblique, and far more clearly dis- 

 joined from the postorbital crests than they are in that species. 



Series E. — This series consists of four large, dark-coloured, 

 male specimens which differ considerably from all those discussed 

 above. The carapace as a whole is moderately convex, with the 

 regions somewhat inflated and the grooves iDetween them well 

 marked. The surface is fairly smooth, Avith oblique strifie on the 

 anterior part and more distinct laised lines on the posterior part 

 of the branchial region. The crests are well defined and shai-p, 

 the epigastric well in front of the postorbital. The epibranchial 

 tooth is large and the exorbital moderately prominent. 



According to Miss Rathbun's analytical key to the species of 

 the subgenus PoUimon these specimens would be referred to 

 P. ho7nbeiokense, described by her from a single male specimen. 

 From the detailed description and figure of that specimen, how- 

 ever, they differ in the lather narrower carapace, in having the 

 margin between exorbital and epibranchial teeth sti'aight or 

 slightly convex instead of concave, and, apparently, in having the 

 inter-regional grooves more strongly marked. 



