3o8 



Records of the Indian Museum. 



[Vol. XVI, 



I am of the opinion that the resemblances between Mictyris and the 

 Scopimerinae are convergent rather than genetic and I cannot 

 beheve that the two have had a common origin distinct from that 

 of the Ocypodinae and Macrophthahninae. 



Apart from the position of Mictyris I differ from Dr. Tesch 

 on a number of points <}f lesser importance.' With more material 

 before me than was at his disposal I believe that I have been able 

 to discover generic characters of more constant value than those 

 utilised by him on p. 41 of his report. 



In the possession of tympana, curious membranous areas 

 found on the meral segments of the legs and sometimes on the 

 thoracic sterna, the Scopimerinae differ from all other Decapoda ; 

 in some of the genera, however, they are ill-defined and in certain 

 species of Tympanomcrus they are altogether absent. The sub- 

 family may be distinguished from the Oc^^podinae by the presence 



Text-fig. i. 

 Endopod of second maxilliped. 



a. Scopimera globosa, de Haan. 



b. Tympanomerus gangeticus , sp. nov. 



of a fully formed pleurobranch above the base of the second 

 walking legs and from the Macrophthalminae by the more oblique 

 position and rudimentary character of the antennules and by the 

 greater breadth of the interantennular septum. 



fringed with short hairs. From the slit-Hke opening thus formed a narrow channel 

 passes forwards on either side to the branchial ca\ity, 



On placing a living specimen of Gelasimiis nciifus in a bowl of water and 

 introducing a little coloured fluid at the base of the chelipeds I found that the 

 fluid was immediately drawn in and expelled in the ordinary way through the 

 upper part of the buccal cavern. I failed, however, to demonstrate that the 

 accessory openings were similarly used in submerged individuals, e\cn though an 

 attempt was made to inject the fluid into the pouch, and think it probable that 

 they are employed only for taking in air. The presence of the fringe of hairs 

 suggests that they are inhalent rather than exhalent. 



' Kor instance I regard Dotilla sisrilloritm as a species of Scupiiiieni, D. 

 clepsydi'odactylus as a synonym of D. intermedia and Cleistostoma liiigiitatuni 

 as a species of Tympanomerus. 



