414 MR. J. R. HENDERSON— A CONTRIBUTION 



body is remarkably flattened, and the hand of the left chelipede is bent almost at a right 

 angle to the rest of the limb ; the left carpus is produced into a strong blunt lobe on the 

 inner margin. The ophthalmic process is narrow and exceeds the ophthalmic scales by 

 nearly half its length ; the distal two thirds are laterally spinulose. Tlie ophthalmic 

 scales are very slightly arcuate externally, and spinulose, the largest spinule being 

 situated at the apex. The antennular peduncles are short, the eyes reaching almost to the 

 middle of the last peduncular joint The antennal acicle reaches the distal end of the 

 penultimate peduncular joint ; it is very slightly produced internally, but not bifurcate, 

 and the inner margin is spinulose. The eyes slightly exceed the end of the antennal 

 acicle on each side. The antennal flagellum is short and fringed with long bairs. 



The hand of the left chelipede is almost smooth externally, but granulated on the 

 upper and lower margins ; the upper margin of the mobile finger is serrate. The ambu- 

 latory dactyli are faintly serrate along the anterior margin and are very long, being 

 exactly twice the length of the propodi when both are measured along the anterior 

 margin. 



It attains a somewhat smaller size than the last species. 



Distrihtifion. Indian Seas {Serbst, Fahricim, Miers); Ceylon {liters). 



10. Diogenes ctistos (Fabr.). 



Pagurus custos, Fabricius, Snppl. Ent. Syst. p. 412 (1798) ; INIilne-Edwards, Hist. Nat. Crust, t. ii. 

 p. 236 (1837) ; iiec Dior/enes custos, Dana. 



Diogenes miles, De Man, Mergui Crust, p. 232, pi. xv. figs. 7-9 (1888). 



Rameswaram {Thurston). Abundant on the S. Indian coast; at Madras it is the 

 commonest species of the genus {J. JR. S.). 



The ophthalmic process is narrow and elongated, exceeding the ophthalmic scales by half 

 its length, and the distal three-fourths are armed with lateral spinules which increase in 

 size towards the apex. The eye-stalks scarcely exceed the penultimate joint of the 

 antennal peduncle ; the ophthalmic scales are subtriangular, with the outer border spinulose 

 and the largest spinule situated at the apex. The antennal acicle is spinulose and bifur- 

 cated, the inner process scarcely reaching the middle of the penultimate peduncular joint, 

 while the outer process extends quite to the end of this joint ; tlie antennal flagellum is 

 moderately long and fringed with long hairs. The antennular peduncle scarcely exceeds 

 the antennal peduncle. 



The hand of the left chelipede is granulated externally, the granules being often less 

 strongly marked in adults on a circvilar area at the lower proximal surface. The lower 

 margin of the hand is somewhat flattened proximally, and usually this part is strongly 

 granulated, while the upper margin is dentate ; the dactylus is granulated externally, 

 but dentate above, and both fingers are provided with bundles of sette on their inner 

 margins. The loft merus is liroad, and the antero-external margin (at the carpal articula- 

 tion) is armed with a row of short spinules ; the left carpus is convex externally and 

 strongly granulated. The ambulatory legs are pubescent, more especially their dactyli ; 

 the anterior surface of the meri and carpi is armed with short stout spines ; the propodi 

 are granulated externally, and their anterior margin, as well as that of the dactyli, 

 is armed with short subspinose tubercles. 



