Cyraonomus//o»j the Andaman Sea. 5G7 



and is uot well differentiated from the receding epistome, so 

 that in an end-on view it is widely open, althou<i;li ventrally 

 it is closed by the external maxillipeds. The efferent 

 branchial channels arc separated, so that the endopoditc of 

 the first maxillipeds (which is so much produced in typical 

 Oxystomes, where the channels lie side by side in the middle 

 line of the palate) is of no great length, being much shorter 

 than the cxopodite. 



In the first maxillipeds the epipodite is well developed, in 

 the second it is almost vestigial, and in the third (external 

 maxillipeds) it is small. 



The external maxillipeds, though the ischium and merus 

 are rather narrow, almost cover the buccal cavern ventrally, 

 extending beyond the base of the antennal peduncles. The 

 merus is produced far beyond the carpal articulation, so that 

 it is not much shorter than the ischium. The flagellum is 

 large, coarse, and completely exposed. No afferent branchial 

 fissure is apparent between the carapace and the base of the 

 chelipeds, this area being completely closed by the coxa of 

 the external maxillipeds. 



The chelipeds are equal, much shorter, and in the male 

 considerably stouter, than the true crawling-legs. 



The first and second pair of true legs are verylong,especially 

 as to the dactylus, and are somewhat compressed ; the third 

 and fourth pair are short, and in claw-like dactyli, and have 

 the dorsal elevation usual for the family. 



The abdomen is large, its breadth, even in the male, 

 corresponding with that of the thoracic sternum ; all its 

 segments are distinct, and the three anterior ones are visible 

 in a dorsal view. In the male there are two pairs of large 

 abdominal appendages modified for sexual pui'poses ; in the 

 female, according to Bouvier, there are only three pairs of 

 abdominal appendages. 



The oviducts, according to Bouvier, open on the coxae of 

 the second pair of true legs. 



The branchial formula given by Bouvier for the European 

 and West Indian species, to which also the Indian species 

 conforms, is as follows : — 



Somites and Podo- Arthro- Pleuro- 



their appendages. branchiae, branchiae, branchia;. Total. 



Vll. (1st maxillipeds). epip. (large). . . . . epip. 



Vlll. (:^nd „ ). vestigial epip. . . . . vest. epip. 



IX. (3rd „ ). epip. (small). 2 . . 2-|-epip. 



X. (chelipeds) .... . . 2 . . 2 



XI. (1st true lcg.«i) . . . . . . 1 1 



3 epip. 4 1 0-{--'5 1'pip. 



