38 SPOLIA ZEYLANICA. 



Station VII. — On the left side of the aru, opposite to the preceding 

 station, just above a sandbank occupied by a colony of small crabs 

 with nearly spherical bodies and long slender curved chelae. I sent 

 a couple of these crabs to my friend Dr. J. R. Henderson at Madraa, 

 and he kindly identified them as Dolilla mycteroides (H. Milne- 

 Edwards) belonging to the family Ocypodidse. In Dr. Henderson's 

 " Contribution to Indian Carcinology " (Trans. Linn. Soc. London, 

 Vol. v., 1893, p. 390) this species is mentioned under an alternative 

 title, Scopimera mycteroides, the generic name referring to the 

 presence of thin, smooth, soft, oval areas on the meropodites of the 

 legs and on the sterna, which have been termed " tympana." In a 

 very large series of this species only males occurred, and Dr. Hender- 

 son teUs me that he has never seen a female. 



From this station I obtained seven examples of the youngest living 

 brood met with during the entire inspection. The first specimen to 

 be found was picked up casually in company with a dead shell ; the 

 other six were obtained by the two divers in about half an hour by 

 the hand-trailing method, which can only be employed in very 

 shallow water. The details are given in the follo\ving table : — 



The presence of a buried colony oil one side of the river and a 

 growing colony on the opposite side should presumably be considered 

 in conjunction with the configuration of the banks at this spot, a 

 rocky point on the one side and a sandy bight on the other, the 

 former causing, the latter indicating, a deviation of the tidal currents 

 and consequent alteration of deposit during the period of maximum 

 sedimentation. 



Station VIII. — In a stretch of the river known locally as the 

 Eraiyattiwu-aru, close above the Kaddaiparichchan ferry (Paikira- 

 turai) ; depth 4-5 feet. At this spot edible oysters of large size 

 occurred, often coated with a yellow encrusting sponge. A placuna 



* These ?efer to the figures on the plate at the end of this article. 



