98 THE VOYAGE OF H.M.S. CHALLENGER. 



the pleon, the carapace gradually projects from the cephalon over the pereion, and the 

 several appendages assume a more permanent character without any sudden change of parts. 



Phyllosoma furcicaudatum (PI. XIId. fig. 1). 



This specimen, taken at St. Vincent on the 26th April 1876, at the surface, is 

 6 - 5 mm. long, and has a peculiar form of caudal termination to the pleon, from which 

 I propose to name it, until its relation to the adult form is determined. 



In general appearance it corresponds to the more advanced form taken off the coast of 

 Malabar by Sir Walter Elliot, and I believe it to be a younger stage of some genus of the 

 Scyllaridse, and as several specimens of Ibaccus have been found in that locality, it is not 

 improbable that it may be the young of that genus. 



The ophthalmopoda are long, but do not extend laterally as far as the margins of the 

 carapace : the ophthalmus is pear-shaped and about one-third of the length of the 

 ophthalmopod. 



The first pair of antennas is slender and carries a short branch at the base of the 

 outer flagellum which supports at the apex a few membranous cilia; the second pair of 

 antennas is longer than the first, slender, and armed on the outer side, at about one-fourth 

 its length from the base, with a strong tooth-like process, which in a stage further 

 advanced is probably developed into the outer marginal angle of the great squamiform 

 joint of the peduncle ; the rest of the appendage appears from its multiarticulate condition 

 to resemble the long flagellum in the other families of the Macrura. 



The second pair of siagnopoda exists in the form of a short squamose plate. 



The third pair consists of a small circular tubercle. 



The gnathopoda and the four anterior pairs of pereiopoda correspond with those of 

 the more mature forms in all excepting what may be specific characters. The Cape 

 Verde specimen is armed with large teeth attached to the several joints of the pereiopoda 

 near the articulations. In the specimen from Waltair, in which the legs are free 

 from this kind of armature, there are no branchise yet developed, and the posterior pair 

 of pereiopoda is still in an incipient stage of gemmation. 



The pleon is remarkable ; it shows no sign of segmentation, and terminates in two 

 long tooth-like processes, one at each posterior angle, each process being firm, rigid, 

 and nearly as long as the pleon. 



Phyllosoma verdense (PL XIId. fig. 2z). 



Habitat. — Taken at St. Vincent, Cape Verde Islands, on April 26, 1876, at the surface. 

 Length 2 "5 mm. to 3 mm. 



