278 



borders are smaller, the horizontal portion of the rostrum is very distinctly bifid, 

 and the spinelets of the dorsal surface of the chelipeds and legs are larger, while 

 the epipodite of the 4th (penultimate) thoracic legs is, as in G. rostrata, a mere 

 tubercle without a lash. 



113 114 118 



Regd. Nos. _:_:. 



Family Uroptychidce. 



Diptycines, A. Milne Edwards and Bouvier, Ann. Soi. Nat., Zool. (7) XVI. 1894, pp. 296, 312-313. 

 Galatheidze (part), Henderson, Challenger Anomura, and Stebbing, Hist. Crnst. 

 Chirostylidie, Ortmann in Bronn's Thier Reich Malacostraca, p. 1149. 



Carapace longer than broad, either depressed with the lateral borders well 

 denned, or convex and subcylindrical, its surface either spinose or perfectly 

 smooth.* Thoracic sternum broad, the last segment more or less atrophied. 

 Rostrum well developed. 



In addition to the abdomen being folded on itself, the tail-fan is tucked in 

 beneath the preceding abdominal somites, the telson being transversely divided. 

 The 1st somite is only partly hidden by the carapace, and the infolded angles of 

 the carapace are held down (as in many Macrura) between the outer angles of 

 this somite and the very prominent antero-external angles of the 2nd somite. 

 The pleura behind the 1st somite are very well developed. 



Byestalks short, no orbits. Antennular peduncles weak, the basal joint not 

 widely dilated : the flagella, especially the lower one short. 



Antennal peduncle 5-jointed, the 3rd joint being quite distinct: the 

 flagellum of no great length. A movable acicle is often present at the outer 

 angle of the 2nd joint of the peduncle. 



The incisor edge of the mandible is serrated. No epipodite is present on 

 the external maxillipeds. 



Chelipeds and next 3 pairs of legs well developed, sometimes very long and 

 slender : the last pair of legs weak and flexed. 



In the males, and often also in the females, a reduced number of the 

 abdominal somites are furnished with appendages. 



Key to the genera of Uroptychidse of the Indian Oligobenthos. 



I. Carapace convex, the lateral borders inflated and not sharply defined: 

 rostrum spiniform : antennal acicle wanting : chelipeds and first 3 

 pairs of legs slender and of enormous length ... ... ... PTYCHOGASTER. 



II. Carapace with the lateral borders very sharply defined: rostrum acutely 

 triangular : antennal acicle long and conspicuous : chelipeds long, 

 next 3 pairs of legs of moderate length ... ... ... UROPTYCHUS. 



* In no Indian Urnptychidx is the carapace transversely rugnlose. 



