240 DK. C. CHILTON ON THE SUBTEREANEAN 



not project beyond the margin of the dactylos ; the extremity is not distinctly marked 

 off into a terminal unguis. 



The second gnutliopod (PI. XXIII. figs. 3, 4) is slightly longer than the first, but is much 

 more slender. The coxa is rectangular, deeper than broad, the lower angles rounded, 

 and with six minute seta? on the lower margiu ; arising from the coxa there appear to 

 be two * gill-plates, one rather larger than the other. The basos is long, nearly straight, 

 the posterior margin bearing seven or eight long setae on the proximal half, and a 

 shorter one at the extremity. The ischium is rather long, one-third as long as the basos ; 

 its j)osterior margin bears three or four small setae. The meros is about as long as the 

 ischium ; its distal extremity bears a fringe of about eight or nine long setoe. The carpus 

 is nearly as long as the ischium and meros together ; it is subtri angular, very narrow 

 at the base, and rather loosely articulated to the meros, so that the distal jiart of the 

 limb can readily turn upon this as a pivot, and hence often appears reversed, as shown 

 in the figure of the whole animal (PL XXII. fig. 1). The anterior margin of the carpus 

 is nearly straight, with a single minute seta at the extremity ; the posterior margin is 

 strongly curved, and thickly fringed with long setae arranged in about twelve transverse 

 rows, a small tuft of two or three being situated on the outer surface near the extremity. 

 On the inner surface (PI. XXIII. fig. 4) the carpus bears towards the extremity a transverse 

 row of four or five setae and three or four separate setae placed more proximally along the 

 middle of the joint. The propodos is longer than the carpus and meros combined ; the 

 anterior margin is straight, giving the limb a somewhat awkward appearance ; towards 

 the end it bears three or four minute setae and two or three at the base of the dactylos ; 

 the posterior margin is strongly convex, the palm occupying more than one-half the 

 whole length ; it is defined by a stout spine and fringed on the outer surface with 

 minute spinules, arranged singly, and a row of six separate long setae running parallel 

 to the palm ; the basal part of the margin below the palm is thickly fringed with long- 

 setae, arranged in about eleven transverse rows as in the carpus. When the propodos is 

 viewed from the inside, the dactylos is seen to extend a little beyond the defining-spine 

 and to fit into a slight depression bordered by four spines, one of which is much longer 

 than the others ; running parallel to the palm is a longitudinal series of from twelve to 

 fifteen obHque rows of long setae, each containing from two to four. The dactylos is 

 similar to that of the first gnathopod, but is not so large and powerful. 



The first percBOpod. (fig. 5) has the coxa (side-plate) and basos entirely simikir to those 

 of the second gnathopod, and, like it, appears to bear a double gill-plate. The ischium is 

 short and of the usual form. The meros is oblong, rather more than half the length of 

 the basos ; its posterior margin straight, with five or six separate setae, the anterior 

 margin slightly convex and with the distal angle a little produced ; it bears a seta near 

 the middle and another at the extremity. The carpus is more than half the length of 



* Though there are certainly two plates attached to the coxa, both in the second gnathopod and in the lirst and 

 second perseopoda, in the male specimen dissected, I have not found them in female specimens, and am not sure that 

 the second plate is a gill-plate. It differs in appearance from the true gill-plate, and might be considered a brood- 

 plate, but it bears no setae on the margin, and I am practically certain that the specimen is a male. 



