REPORT ON THE CRUSTACEA MACRURA. 191 



a sharp point or tooth ; it supports two broad plates that extend as far as but not 

 beyond the extremity of the telson. The inner plate is scarcely longer than broad, 

 ciliated on the posterior margin, and it carries a tooth-like process at the outer posterior 

 angle ; the outer plate, though longer, scarcely extends beyond the posterior extremity 

 of the preceding ; it is bisected at one-fourth its distance from the extremity by a ser- 

 rate diaeresis. 



The telson is quadrate ; the posterior angle on each side is produced into a sharp 

 tooth, while two short prominent teeth stand near the middle of the dorsal surface, and 

 long ciliated hairs fringe the postei'ior margin. 



The specimen here described is a male taken off Manila ; two others, both of which 

 are females, were captured off the coast of New Zealand, and are probably of the same 

 species, since they vary in non-essential details, which are probably only sexual. The 

 great distance between the above localities justifies a description of the female, as far 

 as its characters are distinct. 



The specimen which I take to be the female of Nephrons thomsoni (PL XXV. fig. 2) 

 is generally more slender. The rostrum is longer and somewhat broader anterior to the 

 orbits, but the two rows of teeth corresponding with the lateral margins of the carapace 

 arc closer together and less conspicuous than in the male. The carapace is less granulose, 

 and the median carina of the posterior division, behind the two sharp teeth, is smooth and 

 free from granular markings. The somites of the pleon are smooth and free from the trans- 

 verse depressed line that is conspicuous in the male on every somite except the sixth. 



The first pair of antennae is more slender, and the flagella taper gradually to fine 

 extremities. 



The second pair of antennae is more slender than in the male ; the scaphocerite is rather 

 longer, and therefore not quite so square in form. 



The oral appendages resemble each other. The denticular arrangement, especially on 

 the inner margin of the second pair of gnathopoda, are less conspicuous. 



The first pah' of pereiopoda is more slender and less granulose than in the male, and 

 the inner margin of the pollex is smooth, except that a solitary cusp or tooth is present 

 near the centre ; the double row of ciliated hairs on the inner margin in the male is 

 wanting in the female, and a small sharp tooth is present at the external base of the 

 dactylos. In all other respects the pereiopoda closely resemble those of the male ; even 

 the width between them on the ventral surface is not conspicuously greater. 



The first pair of pleopoda is uni-branched, slender, and feeble, the four succeeding 

 pairs resemble each other, and are biramose, having long, ovate plates, resembling the 

 same in the male except that neither pair supports a stylamblys. 



A second and smaller specimen, taken with the preceding female, differs from it in 

 having a second tooth immediately behind the upper and outer tooth, at the distal 

 extremity of the meros of the first pair of pereiopoda. 



