REPORT ON THE CRUSTACEA MACRURA. 319 



other on the dactylos, come into contact, and acquire a prehensile power ; it likewise 

 carries a basisal branch, which is very short, being about half the length of the meros 

 or third joint ; the first joint of the branch is almost rudimentarily short, and the second 

 is multiarticulate and free from conspicuous hairs. 



The first pair of pereiopoda is chelate and armed with long stiff hairs, and differs from 

 the second and third in being shorter and more hirsute, and in having, as in the 

 second pair of gnathopoda, two fasciculi of spinous or serrate hairs near the carpal 

 articulation, one bunch being in a depression on the anterior extremity of the flexor 

 side of the carpos, while the other corresponds with it on the posterior extremity of the 

 propodos. This arrangement appears to give prehensile power by the bending of the 

 propodos against the carpos. 



The posterior two pairs of pereiopoda are long and slender ; the posterior most so. 



The ventral surface of the pereion (l") is much hidden by the long hairs attached 

 to the coxae of the legs ; the oviducts on the third pair nearly meet in the median line, 

 posterior to which there is a small thelycum and ventral plate much like those of 

 Hemijoenaeus tomentosus. 



The first pair of pleopoda is long and single-branched, the inner branch being rudi- 

 mentary. The others gradually decrease in length ; they are biramose, and the smaller 

 branch increases posteriorly, untfl in the fifth pair the two branches are subequal. 



The telson differs from that in the other species of the genus in being fringed with a 

 thick and closely packed row of hairs, intermiugled with four small spines on each 

 side. The dorsal surface is flat and slightly grooved, and the sides, deflecting, become 

 suddenly depressed, making on each side an angular longitudinal ridge from the base to 

 the distal extremity. 



The branchial arrangement is the same as in the typical species. The oral appendages, 

 and those that belong to the anterior portion of the pereion, are remarkable for the length 

 and rigid character of the hairs that fringe them, whereas the posterior pairs of pereiopoda, 

 as well as the pleopoda, are as remarkable for being free from hairs. 



Hepomadus, Spence Bate. 



Hepomadus, Sp. B., Ann. and Mag. Nat. Hist., ser. 5, vol. viii. p. 189, 1881. 



Supra-frontal margin of the carapace produced to a rostrum. Latero-frontal margin 

 produced to a tooth that corresponds with the outer margin of the first pair of antennae, 

 another that corresponds with the second pair of antennas, and a third over the 

 hepatic region. The pleon is laterally compressed. 



The ophthalmopoda stand on a movable somite ; they are compressed and carry a 

 small tubercle near the base on the inner margin, and the ophthalmus is scarcely of larger 

 diameter than the peduncle. 



