288 DR. J. G. DE MAN ON THE PODOPHTHALMOUS 



differences. The rostrum is styliform in its distal half, very 

 acute, and projects straightly forwards, being never curved 

 upward towards its extremity ; it is continued backwards into a 

 short ridge which does not attain the posterior margin of the 

 carapace, and which in most specimens is slightly flattened or 

 even slightly suleate for a part. The rostram is ^ dentate, 

 the formula being in three specimens ^, in two g, and in the two 

 remaining j; the first tooth, i. e. its point, is placed a little 

 before the middle of the cephalothorax, and constantly a little 

 behind the hepatic spine, whereas in P. indicus this spine is 

 found precisely below, and not before, the point of the first tooth 

 of the rostrum. The distance of the first tooth from the second 

 is a little longer than the distance between the second and the 

 third ; the intervals between the other teeth of the upper 

 margin slightly increase distally, the most anterior tooth being 

 separated from the apex of the rostrum by an interval which 

 is as long as, or even a little shorter than, that which separates 

 it from the preceding. The teeth of the lower border are smaller 

 than those of the upper ; their intervals also increase slightly in 

 length, and the foremost stands closer to the apex of the rostrum 

 than the foremost tooth of the upper border. Whereas the 

 distal half of the rostrum is styliform, the proximal half which is 

 found on the carapace is more or less elevated into a high crest, 

 characteristic of our species. 



The antennal and the hepatic spines are both very small, 

 much smaller than those of P. semisulcatus ; other spines are 

 not found on the carapace. The antennal and the hepatic sulci 

 are very deep in P. semisulcatus, whereas in this species they are 

 faintly defined, especially the latter. The gastro-hepatic sulcus 

 is also faintly defined, just as in P. semisulcatus. 



The first, second, and third segments of the postabdomen are 

 rounded on their dorsal surfaces ; the fourth is keeled, but the keel 

 occurs only on the posterior two thirds of the dorsal line ; the 

 fifth and the sixth segments are also cariuate, the acute keel of 

 the sixth terminating posteriorly in a short acute tooth. The 

 terminal segment is unarmed and provided with a rather deep 

 longitudinal groove on the middle of its dorsal surface. The 

 first, second, fourthi, and fifth segments are marked with a small 

 notch on each side posteriorly. The "ventral plate" of the 

 female much resembles that of P. indicus, M.-Edw. (Spence 

 Bate, I. c. pi. xii. fig. 5), but is somewhat less distinctly circular ; 



