312 bulletin: museum of comparative zoology. 



Potamon (Parathelphusa) convexus (de Man). 



Potamon (Parathelphusa) convexus Rathbun, op. cit., 1905 (4), 7, p. 237, pi. 13 

 (Potamonidae 11), fig. 8, text fig. 56. 



Java : River Tjiliwong, iu Botauical Gardens, Buiteuzorg, 850 feet altitude ; 

 23 ^ 14 9 • -^ fii6 series showing growth variations. 



Potamon (Parathelphusa) dayanus (Wood-Mason). 



Potamon (Parathelphusa) dayanus Rathbun, op. cit., 1905 (4), 7, p. 259, pi. 14 

 (Potamonidae 12), fig. 7. 



India : Maudalay, Upper Burma, in small pond near Theebaw's palace ; 1 9 , 

 31.2 mm. long, 43.3 mm. wide. Comparing this witli a female previously de- 

 scribed from Rangoon (Joe. cit.), the carapace is seen to be smoother (the grooves 

 being partially obliterated). On the right side there are five teeth instead of foijr, 

 an extra and very short tooth being inserted at the base of the first tootii. 



Potamon (Parathelphusa) barbouri, sp. nov. 



Plate 5, figs. 1-2. 



Java: Buiteuzorg; \$ juv., having on the right side the cheliped and first 

 and fourth legs, and on the left side the first and a part of the third and fourth 

 legs. 



Carapace depressed, subquadrate, its length f of its width ; surface punctate, 

 the puuctae connecting by reticulating impressed lines ; short faint granulated 

 oblique lines near lateral margins. Cervical suture rather deep, interrupted on 

 either side. Narrow part of mesogastric region defined only at anterior end, from 

 which a deep groove is continued forward, separating the oblique, slightly curved, 

 rugose epigastric lobes. Considerably behind and outside the latter arise the pro- 

 togastric ridges, which are well defined, acute, crenulated, slightly convex and 

 slightly oblique, stopping far short of the lateral margin and opposite the middle 

 of the second tooth. 



Margin of front and orbits crenulate; lower edge of front about \ as wide as 

 carapace, faintly bilobed by a very broad shallow sinus ; sides of front very ob- 

 lique, upper margin of orbit inclined slightly backward and outward. Antero- 

 lateral teeth five (including the orbital tooth), similar, spiuiform, the first one 

 directed forward, the others obliquely outward; the second is a little longer than 

 the others on its outer margin, which is sinuous. 



Lower margin of orbit granulate, iu ventral view sloping obliquely backward 

 and outward ; a stout spine at inner angle. Merus of outer maxilhped very wide 

 and in a plane almost at right angles to that of the ischium ; the latter is without 

 a furrow. Cheliped 1^ times as long as carapace ; surface of merus and carpus 

 crossed by fine granulated lines, palm sparingly granulated, granules most visible 

 on upper surface ; a sharp subdistal spine on upper margin of merus, and a very 

 strong curved spine at inner angle of carpus ; chela weak (in the young male) ; 

 the greatest length of the dactylus equals the middle length of the palm, and the 



