| OCR Text |
Show 100 DR. J. G. DE MAN ON A NEW FRESHWATER [Feb. 19, with the antero-lateral margin of the carapace, and this anterolateral margin is very faintly crenulate; the granules are much less prominent than in the Soudan species. The postfrontal crest is situated more backwards, so that in this species also the upper margin of the orbits, the extraorbital tooth, and that between the latter and the epibranchial tooth are visible when the carapace is looked at from above. The extraorbital tooth has about the same shape as in Potamon aubryi, but the tooth between it and the epibranchial one is much smaller. The orbits have a different shape ; there is no hiatus near the outer angle, the lower edge of the extraorbital tooth making only an obtuse angle with the lower margin of the orbits. The distance between the inner angle of the infraorbital margin and the front is in Potamon pelii slightly larger, but in Pot. fioiveri a little shorter than half the height of the orbit. The sternum of the male is not thickened near the insertion of the chelipedes, and the male abdomen is also different, the penultimate segment being just as long as its anterior margin is broad. I will not describe the legs, the specimen being still young, but they also do not fully agree with those of P. flower i. Measurements of Potamon jijweri in millimetres : - 8- Width of the cephalothorax 49 ± Length of the cephalothorax 30 Distance between the extraorb. angles 31 Distance between the epibranchial angles 39 Breadth of the anterior margin of the front .... 12k Distance, in the middle, between the anterior margin of the front and the postfrontal crest . . 4| Height of the orbits 6 Breadth of the orbits 9| Distance between the extraorbital and the epibranchial angle 5| Breadth of the posterior margin of the cephalothorax 14^ Distance between the anterior margin of the front and the transverse groove that separates the mesogastric region from the urogastric , . . . 16 Length of the terminal segment of the abdomen . . 6 Length of the penultimate segment 6^ Breadth of the anterior margin of this segment . . 8 Breadth of the posterior margin 10| Length of the larger chela. 44 Length of the fingers 27 Height of the palm at the articulation of the fingers 17 Length of the smaller chela 351 Length of the fingers 22~ Height of the palm at the articulation of the fingers 12 |
