REPORT ON THE CRUSTACEA MACRURA. 175 



the branchiae that belong to one pair of limbs into a distinct compartment from those 

 of the succeeding. 



The first pair of pleopoda in the female (PI. XXI. p) is very slender, uni-branched, 

 and Inarticulate. 



The four succeeding pairs (q) are biramose, the branches narrow and flat, the inner 

 one carrying a rudimentary stylamblys in a well-defined notch. 



The posterior pair is biramose, both branches, broad and flat, form the outer plates of 

 the rhipidura (z., v, v) ; they are spinous, more especially on the upper surface; each 

 being armed with a sharp tooth on the outer distal angle, and the outer is divided by a 

 diaeresis, the anterior margin of which is minutely crenated. 



Observations. — This animal in its details corresponds closely with Nephrops, from 

 which it is separated chiefly by the immature character of the ophthalmopoda, the form 

 of the chela of the first pair of pereiopoda, the compressed character of the rostrum, 

 and the general spinous condition of the surface of the animal. It was taken at a depth 

 of nearly a mile, associated with Nephvopsis orientalis, with which I may have to com- 

 pare it when writing of that species. In general form it closely approaches Phoberus 

 csecus, A. Milne-Edwards, which was taken in the same locality as Nephropsis agassizii. 



Nephropsis, Wood-Mason. 



Nephropsis, Wood-Mason, Joum. Asiat. Soc. Bengal, vol. xliii. pt. 2, 1873. 



Carapace, not including the rostrum, rather more than half the length of the pleon, 

 bisected by a deep cervical sulcus. Pleon dorsally smooth. Telson quadrate. 



Ophthalmopoda small, situated close together beneath the rostrum. 



First pair of antennae furnished with two slender flagella ; first joint of the peduncle 

 without a stylocerite. 



Second pair of antennae without a scaphocerite. 



Mandibles robust and furnished with a three-jointed synaphipod. 



First pair of gnathopoda subpediform, seven-jointed, supporting a two-jointed basec- 

 physis, as long as the appendage, and a mastigobranchia ; on the rest a podobranchial 

 plume. 



The second pair of gnathopoda long, slender and pediform, carrying a small and 

 delicate mastigobranchia and a large podobranchial plume. 



The first pair of pereiopoda is large and chelate ; the second slender and chelate, 

 and the third slender and minutely chelate. The last two pairs are slender and 

 simple. 



The first pair of pleopoda is uni-branched and almost rudimentary ; the others are 

 long, slender and biramose. 



