254 Capt. A. C. MacGilcLrist on Decapod Crustacea 



Chelipeds of female are no lonjjer than tlie ambulatory 

 legs, those of the male are much longer; in both sexes they 

 are more massive and armed with spines which are granular 

 and not \cry acute. The most prominent of these spines is, 

 as in E. zebra, that at the inner angle of the wrist. The 

 palms of the male have no teeth on their upper border, those 

 of the female have 2-4 teeth. Tlie chelipeds are unequal in 

 both sexes, the chief diderence heing in the relative size of 

 the palms; there is little difference in length, and that 

 difference is due mainly to the palm of the right hand being 

 longer as well as stouter than that of the left. 



The ambulatory legs are only slightly compressed ; the 

 upper border of the merus is seldom cristate, but is granular 

 (that of fourth ])air being dentate) and ends in a distal tooth. 



This species difi'ers from E. zebra in having its surface 

 coarsely granular ; no coloured bands on carapace ; rostrum 

 narrower, thicker, and only faintly notched at the tip ; merus 

 of legs not (or very seldom) strongly compressed or cristate. 



Co7nme?}salism. — Fixedly adhering to the carapace and 

 legs of a large male are a few tubicolous worms {Serpnlu) 

 and one small patch of uhat seems to be Foraminifera 

 Perforata {Pohjtrema) . 



At Sta. 291, 49-48 fathoms, two adult males, two ovige- 

 rous females, and several young specimens were got ; at 

 Sta. 296, 47 fathoms, an egg-laden female and a young male 

 were obtained: all are from the Persian Gulf, mud and 

 sand bottom. 



The largest specimens give the following measurements : — 



Ovigerous 



female. Male, 



mm. mm. 



Lengtli of clieliped 11 21 



„ carapace 10 ITo 



„ third pair ol' ambulatory legs . . 12 18-5 



Greatest breadth of carapace 10'8 11*5 



This new species will be figured in an early issue of 

 '' Illustrations of the Zoology of 11. 1. M.S. ' Investigator. 



} }) 



O X Y S T O M A. 



Fam. Leucosiidae. 



Okeopuorus, Riippell. 



Oreophorus reticulatus, Adams and White. 



OrcopJwrus reticulatus, Alcoct, Carcin. Fauna lud., Oxyst. p. 174 and 

 relerences. 



Of this very variable species a single ovigerous female was 



