256 OF THE DEEP-SEA CRUSTACEA 



appendages. Three great groups of Brachyura have 

 been established, namely the Bromides, or primitive 

 crabs, in which the abdomen is still large, and the 

 eyes and first pair of antennae are either unprotected 

 or else fold into common pits ; the Oxystoma, in which 

 the mouth is produced acutely in the middle line ; and 

 the Brachyura vera, whose mouth is cut square, 

 whose abdomen — especially in the male — is small, and 

 whose eyes and first pair of antennae are almost 

 always retractile into well-defined sockets of their 

 own. 



Before the launch of the Investigator, in 1881, 

 practically nothing was known of the Crustacea that 

 live in the depths of the seas of British India, though 

 the late Professor Wood- Mason, when dredging in 

 deep water off the Andamans in the year 1873, had 

 indeed discovered an interesting blind lobster, which 

 he named Nephropsis. Since then, as the result of 

 the Investigators activity, about 275 species have 

 been captured between the meridians of 65° E. and 

 99° E. in the nether waters, from 100 to 2000 

 fathoms deep. 



As in the case of the fishes, these crustacean 

 denizens of the cold and gloomy depths are, as a 

 whole, considerably different from those of the shore 

 in the same latitudes, and include, besides many 

 characteristic bathybial species, a number of forms 

 allied to the littoral species of the temperate zones. 



