216 r>K. C. CHILTON ON THE SUBTERRANEAN 



at the end three or four setse. The carpus is rather longer than the mcros, ohlong; the 

 anterior margin with three spiniform setse and two or three simple setae at tlie end ; the 

 posterior margin straight, with a few simple setse, and in the middle a long " auditory 

 seta." The propodos is similar to the carpus, hut considerahly longer ; the anterior 

 margin armed with four or iive spiniform setse and a few simple ones, the posterior 

 margin having at the extremity a group of two or three simple setse and one " auditory 

 seta." The dactylos is similar to that of the third pair of legs. The spiniform setse on 

 the anterior margins of the carpus and propodos are similar to those on the palms of the 

 second and third pairs of legs, but are smaller and not quite so well marked. 



The fifth and sixth pairs of legs are similar to the fourth, but may sometimes be 

 a little longer. 



The seventh pair of legs is entirely absent in all the specimens that I have 

 examined. 



The first pleopoda (fig. 21) form an operculum completely closing in the branchial 

 plates below. The protopodite appears to consist of two joints, a very short coxa, and a 

 rectangular basos, which is broader than long, and bears on the inner margin three stout 

 sette, dentate at the extremity ; these aj)pear to act like tlie " coupling-spines " to which 

 Stebbiug has drawn special attention in the Amj)hij)oda. The exopodite which forms 

 the operculum is an oval plate bulging downward ; it is about twice as long as broad, its 

 inner margin nearly straight, outer margin very convex, bearing on the distal half about 

 six very delicate plumose setse, with three or four shorter ones at the extremity. The 

 endopodite is narrow styliform, slightly enlarged at the base, somewhat sinuous, sides 

 parallel, extremity rounded and tipped with three or four plumose setse. 



The second, third, fourth, and fifth pleopoda (fig. 22) are all alike and of the usual 

 form. Each consists of a short transverse j)rotopodite, an oval endopodite well rounded 

 at the end and with the margins free from setse, and a longer and rather narrower 

 expedite, which is slightly constricted on the outer margin toward the extremity ; the 

 margin is rather irregular, and bears a few finely plumose setse on the inner side and at 

 the end, with sometimes one on tlie outer side. The number of these setse appears to 

 vary somewhat in the different pleopoda, but 1 have not noticed any other differences 

 between them. 



I have not hitherto met with any special modification of the pleopoda of the male 

 like that occurring iu the Asellidse, ^'^c, and do not know whether such a peculiarity 

 has been recorded in the Anthuridoe. 



The iiropoda (fig. 23) are articulated to the end of the sixth segment of the pleon. 

 The basal portion or peduncle is large, fiat, and nearly rectangular, and reaches nearly to 

 the end of the telson ; it is about two and a half times as long as broad ; the outer margin 

 is straight and bears a few setse on the distal half; the inner portion extends as a fiat plate 

 to the median line of the body, the right or the left uropods often having their inner 

 margins in contact below the telson ; the inner distal angle bears a single small seta. 

 The endopodite is articulated to the posterior margin of the peduncle on its outer half ; it 

 is oblong, more than three times as long as broad, extremity rounded, the end and the two 

 margins being fringed with long setse, which are thickest and longest at the extremity ; 



