obtained hi the Indian Seas. 255 



taken at Sta. 291, Persian Gulf, 49-48 fathoms. Tlie cara- 

 pace is 12 mm. long and 15 mm. broad; the length of the 

 chelipcds is 15 ram. The Ciigs arc miiiuie and numerous ; 

 they (h) not intcrrere with the tight closing on the thorax of 

 the lid-like abdomen. 



This specimen presents the following peculiarities: — The 

 surface and edge of the carapace, the pterygostomial regions, 

 the external maxillipeds, the anterior margin of the thorax, 

 and the chelipcds down to the very fingers are prettily orna- 

 mented in parts with an encrusting growth of Foraminifera 

 [Po/f/tremn miniaceiim, jNIocbius, ' i\lecresfauna von Mauri- 

 tius^). These Foraminifera form dark red irregular jagged 

 processes on the grey-coloured carapace and other parts. 

 The caverns are shallow ; the second cavern has a wide open 

 communication with the third, so wide that they look like 

 one elongate cavern. The floors of the caverns and of the 

 channel which bounds the intestinal region have bead-like 

 grannies scattered over them. The tumid branchial regions 

 are raised to a rugged peak, as in O. reticidatus, var. alci- 

 cornis, but the tip is not bifid. The outer surface of both 

 fingers is smooth, without any trace of rows of pits. 



Of seven Indian Museum specimens from off Ceylon, 

 34 fatlioms, five have fingers exactly as in this specimen, 

 the other two have well-marked rows of pits on the outer 

 surface of the fingers. These Ceylon specimens are also 

 encrusted, but nothing like to the same extent, with the same 

 species of Foraminifera; they have, however, three distinct 

 and separate caverns on either side, and the branchial regions 

 arc tumid, but not raised and rugged. 



Ixoides cornutus, gen. et sp. n. 



This genus agrees with Arcania and Ixa in having the 

 hands much longer than broad, tapering from a swollen base, 

 and the fingers oi)ening in a nearly vertical plane, the tip of 

 the dactylus movable through an arc of about 60°. It is 

 more closely allied to Ixa, but it can be distinguished from 

 either by the following diagnostic points : — The fingers are 

 two thirds the length of the j, aim, or about half the combined 

 lengths of wrist and palm ; the sides of the carapace are 

 produced into two stout, conical, horn-like processes, tapering 

 from tiieir base ; carapace is globular and its median regions 

 are not pronouncedly demarcated by channels or grooves ; 

 the merus of the external maxilliped has its outer edge cut 

 away and bevelled, and this bevelled edge forms the inner 

 wall of the afferent branchial canal ; the front is moderately 



