70 CRUSTACEANS OF THE 



Measurements in millimeters: 



12 3 4 5 6 7 8. 



-^ •■■' 9 d' 9. d' d" 9- 

 Length of the penultimate segment 



of the abdomen 9 7^ 6 4^ 



Breadth of the anterior margin of 



this segment &i. 5j 5 4^ 



Breadth at the two prominences. .8 6^ 5| 4| 



Breadth just behind the middle . . 7| 6 5| h\ 



Breadth of the posterior margin. .8 6^ 5| 5^ 



Length of the meropodites of the 



penultimate legs 21 20 18^ 20 17 15^ 11 14 



Breadth of the meropodites of these 



legs 6i 6 5^ 5! 5^ 4^ 3^ ^ 



Nos 1 and 2 Mount Kenepai, N° 3 Sanggau , No* 4 and 

 5 without definite locality, N^s 6 and 7 Siniai River, 

 N° 8 Java, Buitenzorg. 



Parathelphusa tridentata has been recorded from Sumatra: 

 Lahat (v. Mart.) ; Java (v. Mart, Heller, de Man, Ortm.): 

 Soerabaya (v. Mart.), Buitenzorg (de M., Ortm.) ; Borneo : 

 Singkawang (v. Mart.) ; Timor, Bavian Islands, Solor Is- 

 lands (de M.). 



Perithelphusa, n, subg. 



I propose this nevt^ subgenus for Potamon borneense v. 

 Mart, and two new species described in this Report. It is 

 characterized by the existence of one single, well- 

 developed, acute, spiniforra epibranchial tooth, 

 and by the post- frontal ridge being as little developed as 

 in the subgenus Geothelphusa . In these three species the 

 male abdomen has the same form, its sides converging 

 from the base of the third to the apex of the fifth seg- 

 ment, thence to its extremity narrow. The meropodites of 

 the clifilipedes bear a sharp spine on their superior 

 margin, just behind the distal extremity ; the lower sur- 

 face of these joints is smooth, without a tubercle near the 

 carpal articulation and having the margins entire, not 

 tubercular. 



This new subgenus forms a remarkable transition to 



Notes Iroin the Leytleii INlusieum, Vol. JXXI- 



