CRUST ACE AXS FROM THE TROPICAL ATLANTIC. 363 



is a little more than half the length of the fourth ; the sixth is about three-quarters the 

 length of the fifth. The finger is small and slender. 



The fourth peraeopods have the fourth and sixth joints subequal to the fifth in the 

 preceding pair, but the fifth joint shorter than either of these and about half the len<^th 

 of the second joint. Both the sixth joint and the finger are considerably longer than the 

 corresponding parts in the preceding pair. 



The fifth peraeopods are slender, scarcely equal in length to the second joint in the 

 third pair. The sixth joint is slightly shorter than the fourth or fifth. The fino-er is 

 very slender, with only a small bulb at the base. 



The first uropods have the peduncle equal in length to the coalesced inner branch, 

 the outer margin of the peduncle more faintly serrate than that of the branch, the 

 inner margin of both smooth ; the outer branch is spine-like. The second uropods are 

 more slender than the first, with peduncle and inner branch subequal, serrate only 

 along the inner margin, and having a spine-like outer branch, which is a little thinner 

 and a very little longer than that of the first pair. The third pair have the peduncles 

 a little longer than the outer branch, but considerably shorter than the coalesced inner 

 branch ; the outer is two-thirds of the length of the inner branch ; the outer maro-in 

 of the inner and the inner of the outer branch are serrate. 



The specimen, a female with setiferous marsupial plates, measures three- twentieths 

 of an inch, antennae and uropods included. 



Habitat. Atlantic. Lat. 3° 0' 8" N., long. 7" 43' W. Taken at noon from a depth 

 of 50 fathoms. 



The specific name refers to the general likeness which this species presents to the 

 species tullherrii, pacifica, and concors. Yet it diff'ers from all three in the relative 

 proportions of the joints of the fourth peraeopods, and by the different character of the 

 fifth peraeopods, especially in regard to the finger; moreover, the proportions of the 

 uropods are different, not to mention other marks of distinction which separate it from 

 one or other of the species in question. 



SciNA UNciPES, n. sp. (Plate LIV. B.) 



The outline of the head was probably broadly truncate between the antennae, but 

 owing to an accidental damaging of the specimen this cannot be affirmed with certainty. 

 The telson is triangular, scarcely a third of the length of the peduncles of the third 

 uropods. 



The eyes resemble those of Scina similis. 



The first antennae are stout, equal in lengtli to the hinder half of the pleon, from the 

 base of the fourth segment to the extremity of the uropods. The first joint of the 

 flagellum has twelve teeth on the outer margin and about sixteen on the inner, over 

 which project some setules, and a rather slender supply of filaments. The second joint 

 is only a small stump, without any setae ; but this is probably not its normal condition. 



