540 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. XXXV. 



posterior lobe; hand longer than the preceding joints combined, 

 oblong, the palm very oblique and extending beyond the middle of 

 the posterior margin, denned above by a prominence bearing a pair 

 of stout spines, and bearing below the middle two broad lobes armed 

 with spines and separated by a narrow sinus ; the stout curved finger 

 bears a small rounded prominence near the base of the inner margin ; 

 the tip fits into a concavity at one side of the upper end of the palm: 

 a couple of large spines on the edges of this concavity and a row of 

 short spines extending distally from it along the inner surface of 

 the hand. The smaller gnathopod has the carpus triangular, about 

 as long as wide, with a broadly rounded posterior lobe; hand with 



Fig. 45. — M;era spixicauda. ah. segment of the abdomen; gn^, first gnathopod; 



<I>1 2 , SECOND GNATHOPODS OF THE RIGHT AND LEFT SIDES ; t, TELSON ; «r 1; FIRST UROPOD ; 

 UVz, THIRD UROPOD. 



the palm less oblique and much less uneven than in the larger gnath- 

 opods, the lobes on the lower half being represented only by a 

 slight prominence; the finger has a low prominence on the inner mar- 

 gin near the base, and the tip fits into a sinus near the spiniferous 

 prominence at the upper end of the palm; this sinus is not nearly 

 so large as in the larger hand but it is furnished with two large 

 spines on its upper side on the inner surface of the hand. 



First two peneopods slender, the dactyl about a third the length 

 of the propodus. Basal joints of the last three pera?opods about twice 

 as long: merus expanded, especially in the last two pairs; dactyls 

 about a third the length of the propodi. First five abdominal seg- 



