Indian Deep-sea Crustacea. 287 



white, flagella bright red ; antennal base and proximal half of 

 flagellum white, distal half of flagellura pale orange; large 

 cheliped white, except ringer and thumb, which are pale 

 orange, extreme tips of finger and thumb white ; hands and 

 fingers of second, third, and fourth pairs of walking-legs 

 bright red, remainder of legs white ; lower surface of thorax 

 and abdomen white. 



Family Callianassidae . 

 CALASTACUS, Faxon. 

 Calastacus felix, sp. n. 



This species differs from Calastacus stilirostris and C. inves- 

 tigatoris in the following particulars : — the carapace is covered 

 with a scanty growth of short, stiff, yellowish, forwardly 

 directed hairs, springing either singly or in groups of two 

 or three from the bottom of small pits in the surface of 

 the test, these hairs being both longer and stouter on the 

 gastric region than elsewhere. The lateral margins of the 

 rostrum, like those of Calastacus investigator is, extend back- 

 wards a short distance on either side of the carapace as 

 outstanding ridges, each bearing a couple of spines, the ante- 

 rior pair of which is much larger than the posterior. A dorsal 

 carina extends from the base of the rostrum to the posterior 

 margin of the carapace, where it ends on a small lobe pro- 

 jecting into the gap left between the backwardly projecting 

 pleurae of the carapace. The tubercle at the posterior 

 termination of the carina of C. investigatoris is only repre- 

 sented in this species by a small irregularity of the carina. 

 Occupying the anterior | of the gastric region is a line of 

 small, sharp, forwardly projecting teeth arranged in the form 

 of a horseshoe, with its free ends turned backwards. The 

 rostrum bears on each side a pair of asymmetrically arranged 

 teeth. 



A small, somewhat irregular, but pigmeuted cornea is 

 present. 



Of the great cheliped the wrist, near its junction with the 

 hand, is considerably wider than the wrist-hand joint, espe- 

 cially on its lower margin, which projects as a blunt tooth. 

 In the other two species the carpo-propodal joint is as wide 

 as the widest part of the carpus. 



Near the centre of the cutting-edge of the immobile finder 

 is a large tooth. The carpus, propodus, and dactylus are 

 covered with long, coarse, but somewhat sparse hair like that 

 on the carapace. 



The second pair of walking-legs is absent. 



