1901.] CRUSTACEAN FROM THE SOUDAIf. 101 



Length of the legs of the last pair 53 



Leugth of the meropodites of these legs 17 



Breadth of the meropodites of these legs 5| 



Length of the daotylopodites 11 



Thickness of the cephalothorax 21 



Remm-Tcs on Potamon (Potamonautes) hilgendorfi Pfeffer. 



Prof. Pfeffer, of the ISTaturhistorisches Museum of Hamburg, 

 was so kind as to present me with two type specimens of Telphusa 

 MJgendorfi Pfeffer, both males from tlnguu. As Pfeifer's de- 

 scription (' Uebersicht der von Herrn Dr. Pr. Stuhlmann in 

 Aegypten, auf Sansibar und dem gegeuiiberliegenden Pestlande 

 gesammelten Eeptilien, Amphibien, Pische, Mollusken und 

 Krebse,' Hamburg, 1889, p. 32) is very short, the following 

 remarks will, I think, be welcome. 



The larger specimen has lost its chelipedes ; in the other both 

 are present, but Dr. Pfeffer had added two detached chelipedes, 

 that, as regards their size, should belong to the larger male. In 

 the first place I will remark that, as Pfeffer Hkewise writes to me, 

 the true Pot. hilgendorfi Pfeffer is a different species from that 

 which has recently been described under the same name by Hil- 

 gendorf (' Die Land- und Siisswasser-Dekapoden Ostaf rikas,' 

 1898, p. 9, fig. 3), and which inhabits the country around Kilima- 

 njaro. 



The cephalothorax of both males is depressed, especially behind 

 the cervical suture. The gastric region appears, however, very 

 shghtly arcuate, both transversely and from before backwards. 

 Hilgendorf, on the contrary, describes the cephalothorax of his 

 species ,as " deutheh gewolbt." In Hilgendorf 's species the antero- 

 lateral margin of the carapace is described as extending laterally 

 beyond the outer orbital angle somewhat farther than the orbits 

 are broad, but in the type specimens of Pot. hilgendorfi Pfeffer they 

 extend laterally somewhat less than the orbits are broad. In the 

 species described by Prof. Hilgendorf the lateral portions of the 

 cervical suture are indistinct and invisible ; in Pfeffer's types, how- 

 ever, they are deep and distinctly developed, though not reaching 

 to the postfrontal crest. In both species an epibranchial tooth 

 is ivanting. That part of the lateral margin which is situated 

 between the rather acute extraorbital angle and the lateral ex- 

 tremity of the postfrontal crest is very obliqiie, distinctly granu- 

 lated, and makes a right angle with the upper margin of the orbits ; 

 in Hilgendorf s species, on the contrary, the outer orbital angle 

 is described as " stumpf winklig." In the young male the lower 

 margin of the orbits presents no trace of a hiatus ; but just 

 below the extraorbital angle in the larger male I observe a quite 

 shallow incision only on the left side ; in the species from Kilima- 

 njaro, however, the incision is small, but usually deep. 



The antero-lateral margin, the postfrontal crest, and the orbital 

 margins are distinctly granular or crenate, the postfrontal crest is 

 rather prominent and only interrupted by the mesogastric suture ; 



