170 DR. J. G. DE MAK ON THE PODOPHTHALMOTJS 



between the external orbital angles to the length of the cephalo- 

 thorax is as 20:16g, in S. quadrata, Y^d^v.,=ungulata, M.-Edw., 

 = affinis, de Haan, as 20 : 15|^. In the proportion of the distance 

 between the external orbital angles to the breadth of the front, 

 S. aspera completely agrees with S. quadrata, Fabr. The penul- 

 timate joint of the male abdomen has a somewhat different form, 

 being smaller than in 8. quadrata, Fabr. The legs of both 

 species almost completely agree with one another, the only 

 differences observable being the following : — The oval transverse 

 tubercles, which occur on the upper margin of the mobile finger 

 of the male, number 16 or 17 in 8. aspera, whereas in the 

 typical specimen of 8. quadrata there are only 11-13, of 

 which the proximal 7-9 tubercles are more distinct than the 

 others. 



The species of this section seem to be comparatively rare, for 

 few specimens exist in museums ; but when a more extended 

 series is available for comparison, I am disposed to believe that 

 the differences I have indicated will be found to be individual. 

 The Leyden Museum contains only a single male specimen from 

 an unknown locality ; this specimen has 12-13 tubercles on the 

 mobile finger, and certaialy belongs to the true 8. quadrata, 

 Pabr. ; it was, however, referred by me to 8. ajffinis, de Haan, 

 when I worked out the Leyden collection. Sesarma aspera 

 with 17 tubercles on the mobile finger, S. quadrata with 11-13, 

 S. ungulata with 8, and S. afflnis with 7, are, I think, mere 

 local or perhaps only individual varieties of one and the same 

 species (^8. quadrata, Fabr.). 



Sesarma aspera, Heller, has been recorded from Ceylon, Madras, 

 and the Nicobar Islands. 



93. Sesaema Melissa *, n. sp. (PI. XII. figs. 5-7.) 

 One male specimen was collected in Kisseraing Island. This 

 species agrees almost completely in all its characters with Heller's 

 Sesarma aspera, and differs from it only by the different form of 

 the prominences with which the upper margin of the mobile finger 

 is armed, by its somewhat more slender ambulatory legs, and by 

 the dactylopodites being comparatively a little shorter. 



In the structure and dimensions of the cephalothorax, and in 

 the form of the front and of the male abdomen, both species are 

 alike. 



* Melissa, the daughter of Oceanus. 



