REPORT ON THE CRUSTACEA MACRTJRA. 39 



logs in general appearance, but consists of only five joints, or two less than the normal 

 number, the coxa and basis being consolidated into one, and the dactylos absent. The 

 second pair of gnathopoda is also subpediform, and consists of six joints, the coxa and 

 basis being fused into one, and differs from the normal pereiopod in the form of the 

 dactylos only. Although these two pairs are each described as being subpediform, and 

 differing from each other only in the absence of a single joint, yet in their general 

 appearance they vary considerably. The first joint, or coxa and basis united, in the first 

 pair carries a mastigobranchial plate, and a slender basecphysis, consisting of a long basal 

 joint and a terminal multiarticulate nagellum as long as the primary branch. In the 

 second pair the first joint, or coxa and basis united, carries a basecphysis not half the 

 length of the primary branch ; besides this the mastigobranchial plate is longer and more 

 slender, and it also supports a branchial stem carrying rudimentary papillge. In the first 

 pah- the ischium is short, in the second it is long. In the first pair the meros is long, at 

 least four times as long as the ischium ; in the second it is scarcely so long as the 

 ischium, and armed at the inner distal extremity with two strong teeth. The carpos in 

 both pahs bears a corresponding resemblance, but the propodos in the first pah- termin- 

 ates the appendage as a semicircular terminal joint thickly fringed with hairs ; in the 

 second pair the propodos is long, cylindrical, and furnished with hairs on the lower 

 margin, and the dactylos, which is short and rounded, ends in an obtuse point, and 

 has the inferior margin thickly fringed with strong hairs. 



The first pair of pereiopoda has the left hand wanting in our only specimen, but the 

 right is well developed ; the meros is long, and excavated beneath on the anterior portion, 

 the inner side of which is armed with a sharp strong tooth. Into this hollow the infero- 

 posterior portions of the carpos and propodos fall when folded back, and the prominent 

 tooth acts as a guide to direct it to its position ; the carpos is triangular, having the 

 broad side directed forwards, against which the propodos articulates during its entire 

 depth ; the propodos is deep, but scarcely more so than the carpos at its approximate 

 extremity, but it increases as it approaches the dactylos, the anterior upper angle is pro- 

 duced to a sharp-pointed tooth, the inferior angle into a long polliciform process pointed 

 at the extremity, and curved upwards ; the dactylos is about as long as the propodos is 

 wide, it is arched on its upper margin, and terminates in a point ; the lower incisive 

 margin is nearly straight, except for a small cusp or tubercle near the middle. 



The second pair of pereiopoda is much smaller than the first ; it is chelate, having 

 the hand, when the dactylos is closed against the propodos, of a long ovate form. 



The third and fourth pairs of pereiopoda are longer than the second, but scarcely as 

 robust ; they have the propodos long, and the dactylos short and pointed. 



The fifth pair is more feeble than either of the preceding, and appears to be 

 reversed in its articulation with the body. It is long and slender, and terminates in a 

 long propodos, distally tipped on the inner side with long hairs and a sharp dactylos. 



