242 CARCINOLOGICAL STUDIES. 



are still of equal size and that the cephalothorax is not 

 yet as much convex. 



The cephalothorax of Geotelphusa crassa , the type-spe- 

 cimens of which I examined in Paris, is in adult indivi- 

 duals about once and a half as broad as long, but in the 

 younger it appears comparatively longer. The upper sur- 

 face is a little convex from behind forwards , somewhat 

 more in the adult than in the young, though not in such 

 a degree as in Geot. picta v. Mart., and also somewhat 

 convex transversely. The upper surface is punctate, but 

 for the rest quite smooth ; the points are somewhat coarser 

 on the gastric region, finer and less numerous on the rest 

 of the upper surface. The cervical suture, interrupted as 

 in Geot. picta on each side of the posterior part of the 

 gastric region , is rather shallow. The two slightly erose , 

 postfrontal elevations, situated behind the front and sepa- 

 rated from one another, as usually, by the median frontal 

 furrow, are scarcely distinct; other traces of the postfron- 

 tal crest are completely wanting. The front, as far as it is 

 visible when the carapace is looked at from above, is bor- 

 dered anteriorly by a straight or a little concave, slightly 

 cristate margin, which passes with very obtuse 

 and rounded angles into the upper margin of the 

 orbits ; that slightly cristate margin forms the anterior 

 margin of the front. The anterior part of the front , how- 

 ever, lying before the said margin, is deflexed downwards 

 and backwards, and united with the epistome, as in the 

 preceding species. The orbits are transverse and a little 

 broader than long, the proportion of their breadth to their 

 height being as 3 : 2^3- The anterior frontal margin and 

 the upper margin of the orbits are perfectly smooth, but 

 the arcuate lower margin , which passes directly into the 

 upper without a hiatus or interruption at the external an- 

 gle, appears very finely crenulate. The external angle of 

 the orbits is little prominent, not tooth-like. The lateral 

 margins of the cephalothorax are arcuate. The antero-la- 

 teral ones , being long and extending until a little before the 



Notes from ttie Leyden Museum, Vol. XIV. 



