REPORT ON THE CRUSTACEA MACRTJRA. 855 



The description given of the preceding species agrees with the present form, except 

 that the general structure is stronger and more pronounced in this specimen, which 

 would have been selected as the type had not certain important parts, more especially 

 the peculiar chelate appendages, been wanting. 



In this species I had the opportunity of examining the oral appendages, which I was 

 not able to do in Stylodactylus discisslpes. 



The mandibles (fig. 2d) have a broad psalistoma connected with the molar prominence, 

 furnished with a few strong dental processes, and carry a biarticulate synaphipod fringed 

 with hairs, of which the longest are attached to the first joint. 



The first pair of siagnopoda (fig. 2e) consists of three short branches ; the inner is short, 

 flat, curved, and distally fringed with a few hairs ; the second or median is bat-shaped, 

 being narrow at the base, and distally broad, flat, the distal margin being rounded and 

 fringed with small cilia ; the outer branch is short, cylindrical, and bifid at the extremity. 



The second pair of siagnopoda (fig. 2f) consists of a cylindrical and two broad but 

 small plates on the inner side, the margins of which are fringed with hairs ; the first has 

 the margins parallel, the second is bat-shaped, and the third is short, cylindrical, and 

 tipped with hairs ; on the outer side is a large, broad, flat, squamous plate, fringed with 

 hairs, of which those on the posterior extremity are sufficiently long to reach to the 

 posterior extremity of the branchial chamber. 



The third pair of siagnopoda (fig. 2g) consists of one large and one small squamous 

 plate, beyond which, fringed with hairs, is a narrow subcylindrical median plate tipped 

 with hairs, and on the outer side a broad squamous plate of great tenuity, from the inner 

 margin of which arises a slender cylindrical branch that tapers to the extremity and is 

 tipped with hairs ; at the base of the plate stands two membranous plates. 



The second pair of gnathopoda, as well as all the pereiopoda except the last pair, 

 carry attached to the coxa a short, broad, flat, mobile plate, fringed on the upper surface 

 with hairs, which is the rudiment of the mastigobranchial appendage. 



All the other parts bear a close resemblance to those described in other species, and 

 from which I am not able to determine any specific distinction besides those mentioned. 



Observations. — This species was found associated with Stylodactylus discissi'pes, from 

 which it differs chiefly in the length of the rostrum and the number of teeth that ornament 

 it, as also from Stylodactylus serratus of the West Indies, from which it may also be 

 determined by the presence of small spines on the anterior margins of the carpal joints of 

 the second pair of gnathopoda and the first two pairs of pereiopoda. 



Stylodactylus bimaxdlaris, n. sp. (PI. CXXXVIII. fig. 3). 



Carapace less than one-third of the length of the animal ; rostrum about once and a 

 half the length of the carapace, and armed on the upper margin with thirty-six fine 



