REPORT ON THE CRUSTACEA MACRURA. 719 



animal, not including the rostrum ; it is smooth generally except for two small tubercles 

 in the median line, one standing on the postcardiac region, the other on the frontal 

 crest at the base of the rostrum, which projects anteriorly in a straight line and 

 is half the length of the carapace, it is armed on the upper margin with five or 

 six small teeth, and with one on the lower margin near the apical extremity. The 

 orbit is defined by a small, sharp tooth at the outer angle, whence the frontal 

 margin recedes to the fronto-lateral angle, which is defined by a sharp and well- 

 developed tooth. 



The first two somites of the pleon are short, subequal in depth with the 

 carapace, and have the lateral margins fringed with hairs. The third somite is 

 continued dorsally in the same line to about twice the length of the preceding two, 

 and is then bent at an acute angle downwards and forwards to the posterior part 

 of the lateral margin, which lies subparallel to the dorsal surface, thus producing the 

 dorsal surface into a huge posteriorly directed projection or hunch. The fourth somite 

 is short, articulates with the third at a right angle, and appears to be incapable of 

 extension in a more direct line with the preceding somites. The fifth somite is long 

 and narrow. The sixth is about the same length as the carapace or three times as long 

 as the fifth somite, and terminates abruptly in the median line posteriorly ; it is 

 armed on each side of the posterior margin with a long and slender tooth and inferiorly 

 with another. The lateral margins of all the somites are fringed with hairs, which 

 appear to increase in length posteriorly. The telson is long and narrow, fringed at the 

 extremity with small hairs and on the lateral margin with small spinules. 



The ophthalmopoda are pyriform, tolerably robust, and about the length of the 

 rostrum. The ophthalmus is large and ovate. 



The first pair of antennae has the first joint of the peduncle longer than the ophthal- 

 mopod and curved to allow space for the movement of that organ ; the second and third 

 joints are short and cylindrical, reach as far as the apex of the rostrum, and support two 

 short and apparently immature flagella. 



The second pair is furnished with a scaphocerite that is about the same length as the 

 peduncle of the first. 



As there is only one specimen of this species in the collection, I have not attempted 

 to dissect out the oral appendages, which have, therefore, not been examined further 

 than what can be observed of them in their natural position. The mandibles are situated 

 only a little less than half the distance between the frontal and posterior margins of the 

 carapace; they have no synaphipod, and are placed between two prominent labra. 



The gnathopoda and pereiopoda appear to be incompletely developed ; they each 

 consist of six joints and a long basecphysis, of which the anterior is the shortest and the 

 third pair of pereiopoda the longest, whereas the fourth and fifth pairs are as yet in an 

 incipient condition. 



