I9I5-] 



Fauna of the Chüka Lake : Crustacea Decapoda. 



227 



this period of the year the water was quite salt. Dater, in September, when the 

 water was fresh, no specimens could be discovered. 



No species of Dotilla were found on the seashore outside the lake. It is not 

 improbable that the violence of the breakers on the coasts of the Bay of Bengal 

 renders such a situation impossible for small and delicate crabs and that they can 

 only flourish in more sheltered spots. Ocypoda, perhaps, is able to save itself by its 

 extremely rapid movements. 



A number of very small specimens, obtained by Dr. Annandale in the Knnur 

 -backwater, near Madras, are also referred to this species. In none of these indivi- 

 duals is there any trace of the large teeth on the ringers of the chelae and the identi- 

 fication is, in consequence, somewhat doubtful. 



The type specimens of D. clepsydrodactylus were found at False Point on the sea 

 face of the Mahanaddi Delta, a locality less than a hundred miles distant in a direct 

 line from the Chilka I,ake. Mr. F. H. Gravely has recently obtained a fine series of 

 the species at Balasore, a little to the north of False Point. 



Dotilla myctiroides (Milne-Edwards). 



1900. Dotilla myctiroides, Alcock, Joum. Asiat. Soc. Bengal, L,XIX, p. 368. 



A single example of this species, the carapace 6-9 mm. in breadth, was found on 

 the shore of an island in the outer channel near Manikpatna. The specimen was 

 obtained in March 1914, when the water in the channel was salt. 



A large ovigerous individual of this species was recently obtained by Dr. Annan- 

 dale in the Ennur backwater near Madras. The 

 specimen bears an enormous number of eggs, so 

 many that the abdomen projects backwards 

 in a straight line with the carapace, the masses 

 of eggs bulging out on either side of it and of 

 the legs. In this example, precisely as in the 

 ovigerous females of D. pertinax mentioned 

 above, the abdomen is quite narrow and in 

 external appearance closely similar to that of 

 the male (cf. text-figs. 8a and 8b). It is com- 

 posed of seven separate segments and it seems 

 probable that this number is found in both 

 sexes of all species of the genus and that de 

 Haan was in error in his statement that in 

 females of D. sulcata there are only five. 



The supposed scarcity of females in the genus Dotilla has often been the subject 

 of comment; but this, I believe, is to be explained by the close similarity in the 

 form of the abdomen in the two sexes. It is, however, curious that ovigerous 

 females are not more abundant; the eggs, which are poorly protected and must be 

 a great encumbrance to the mother, are perhaps only carried for a very short period 

 and it is noteworthy that the ovigerous specimen of D. myctiroides from Ennur was 



a. o. 



Fig. 8. — Dotilla myctiroides (H. Milne- 

 Edwards). 



a. Abdomen of male. 



b. Abdomen of female. 



