I 



192 DE. C, CHILTON ON THE SUBTEEEANEAN 



The propodos is oblong; outer margin slightly convex, with one or two setae at the 

 extremity only ; inner margin slightly convex and densely fringed with setae, except at 

 the base. The dactylos is similar to the propodos, but much shorter and narrower ; it 

 bears setse arranged as in the propodos, two or three of those at the extremity being 

 very long and robust. 



First appendage of perceon (PI. XVII. figs. 1, 2, 3). In the male these form large 

 weU-developed subchelate gnathopoda, very similar in general appearance to those found 

 in many Amphipoda. In the female they are similar, but much smaller. Unfortunately,, 

 the only female specimen that I have of this species has been mounted dry on a slide, and 

 I am, therefore, unable to give a full detailed description of its gnathopods, but so far as 

 I can see they are very like those of Phreatoicus typicus as described later on [see p. 199, 

 PI. XVIII. figs. 7, 8], except that they are stouter and rather better supplied with setse. 

 The following description therefore applies to the male only. 



The coxa (epimeron) is small, attached to the anterior portion of its segment, and is 

 more or less ankylosed to it ; it is free from setse, and is emarginate below to receive 

 the basos. The hasos is longer than the ischium; it is constricted at the base and has 

 three small tufts of setse on the posterior margin. The ischium is similar to and nearly as 

 long as the basos ; it has two or three tufts of setse on the posterior margin and two stout 

 setse at the middle of the anterior margin, where it is slightly convex. The meros has a 

 small tuft of setse at the extremity of the posterior margin, which is straight : this joint 

 is expanded distally, produced anteriorly and inward, and is hollowed out at the end 

 to receive the rounded end of the large propodos ; the inner margin of the cup-shaped 

 socket thus formed is very densely fringed with long straight setse iirojecting radially 

 inward (PI. XVII. fig. 3). The carpus is small, sub-oblong, the posterior margin with a tuft 

 of setae tow-ards the extremity and one or two sejiarate setse placed more proximally, the 

 anterior margin completely covered by the proj)odos and meros. The propjodos is very 

 large, forming much the largest jDortion of the whole limb ; it is produced backwards 

 beyond the carpus into a rounded lobe which rests back on to the meros ; the whole joint 

 is oval in outline, the anterior margin very convex and without setse, with the exception 

 of a small tuft at the extremity ; the posterior margin slightly sinuous, fringed with short 

 setae ; the palm oblique and well defined, armed with a rounded lobe near the base of the 

 dactylos, followed by four very short triangular spines placed on slightly rounded lobes : 

 these spines decrease in size as they recede from the dactylos ; between the base of the 

 dactylos and the rounded lobe is a row of 7 to 8 setse, and from the lobe toward the end 

 of the palm is a row of simple setse, each with a distinctly enlarged base, and near this 

 row a few scattered setse on the surface of the propodos. The dactylos is strong, as long 

 as the palm, both margins fringed with a few minute spinules, the extremity forming a 

 distinct nail, with a small secondary nail on the inner margin at its base. 



The second appendage oftheperceon (PI. XVII. fig. 4). — The coxa is similar to that of tlie 

 first ap])endage, but is sHghtly larger and is distinctly marked off from its segment. 

 The hasos is narrow at the base, but widens out at the middle, where the breadth is nearly 

 half the length, and it narrows slightly again toward the distal end; the anterior margin 

 is fringed throughout its whole length with short, stout setse ; the posterior margin bears 



