279 

 PTYCHOOASTEB, A. M. Edw. 



Ptychogaster, A. Mihro Edwards, Bull. Mus. Comp. Zool. VIII. 1880, p. 63: Henderson, Challenger Anomura, 

 p. 170: Milno Edwards and Bouvier, Ann. Sci. Nat. Zool. (7) XVI. 1894, p. 301, and Mem. Mns. Comp. Zool. XIX. 

 No. 2, 1897, p. 117: Bouvier, Bull. Soc. Entomol. France, LXV. 1896, pp. 307-312. 



Chirostylus, Ortmann, Zool. Jahrb., Syst. VI. 1891-92, p. 244. 



Oastroptychus, Caullory, Caadan Crust. Ann. Univ. Lyon., 1896, p. 390. 



Carapace convex, subcylindrical, broader behind than in front, usually 

 spinose, the gastric region well defined : it is held down by the incurved postero- 

 lateral angles. Thoracic sternum broad its last segment very much reduced. 

 Rostrum slender and spiniform. 



Abdomen folded on itself, the pleura behind the 1st well developed : tail-fan 

 symmetrical ; telson transversely fissured and folded under the preceding somites 

 with the caudal swimmerets. 



Eyes well pigmented. Antennular peduncles weak and flexed, the last 

 joint elongate ; the lower flagellum very much shorter and slenderer than the 

 upper. Antennal peduncles slender, five-jointed without a movable acicle : the 

 flagellum of no great length. 



Mandibles with an incurved palp and with the edge of the incisor process 

 serrated. 



The exopodites of all the maxillipeds are flagellated, and the external 

 maxillipeds are pediform. None of the maxillipeds and none of the thoracic 

 legs have epipodites. 



The chelipeds and next 3 pairs of legs are slender, spiny and of enormous 

 length ; the last pair of legs are weak and infolded. 



In the male the 1st and 2nd abdominal somites carry paired appendages 

 modified for copulation, and rudimentary paired appendages are present on the 

 next three somites : in the female slender paired appendages are present on the 

 2nd-5th somites. 



The eggs are large and not numerous. 



In both the Indian species the branchial formula is as follows : 



Somites and their r Arthrobranchia,. 



Total. 65 = 14 (no epipodites). 



