/ 



species is common to Japan and the East Indies, one has been described from 

 Australasia, and recently two more have been added from the Oriental region. 



Of the 2 Corystoid genera that occur in Indian deep waters : 



Trichopeltarium is only known elsewhere from the Caribbean Sea, while 

 the closely allied Trachtcarcinus is from the Pacific slopes of Central America. 



GoNiosoMA, PiLUMNOPLAX and Carcinoplax may be regarded as shallow- water 

 Indo-Pacific genera, Pilumnoplax occurring also in the South Atlantic. 



Of the genera here referred to as peculiar (so far as is known) to Indian 

 Seas, two require special notice in connexion with this question of geographical 

 distribution. 



The first of these is the Dromioid genus Arachnodromia. This is so 

 extremely like Prof. A. Milne Edwards' Homolodromia from the Caribbean Sea, 

 that I should have taken it almost for the same species had not M. Milne 

 Edwards stated that the form described by him has neither antennulary nor special 

 orbital fossae. Our species has common antennulo-orbital fossae not essentially 

 different from those of Dromia. 



The second is Benthochascon, which is very intimately related to the Gulf 

 of Mexican Bathynectes. The last named genus, however, is also known from 

 the Eastern Pacific. 



The Composition of the Brachyuran Fauna of the Indian OH(/o-benthos. 

 This, so far as is known, is as follows : — 



Catometopa 7 species, or 13"2 per cent. 



Cyclometopa (including Corystoidea) 8 „ „ 15'0 „ „ 

 Dromidea (Dromidss and Homolidse) 9 „ „ 16'9 „ „ 

 Oxystoma {including Raninidse) 14 „ „ 264 „ „ 



Oxyrhyncha 15 „ „ 283 „ „ 



The large proportion of Oxyrhynchs and the small proportion of Cyclomet- 

 opes and of Catometopes (due regard being paid to the relative proportions of 

 these groups in their entirety) is interesting to those who do not accept the view 

 that the Oxyrhynchs as a whole are the highest Crustacean developments. 



The very large proportion, relative to the size of the group, of Dromidea is 

 also of much interest. 



The Bathymetric Range of the Indian Beep-sea Brachyura. 



Only one species — Ethusa investigatoris — has been dredged in 1200-1300 

 fathoms. 



The following three species occur between 800 and 1,000 fathoms : — 



Hypsophrys superciliosa 740-931 fms. 

 Ethtisa desciscens 931 „ 



Ethusa gracilipes 836 „ 



