32 T. V. IIODOSON. 



The metasoiue comprises three or four .segments and a urosome, a circumstance 

 which docs not seem U> depend upon age. In many individuals of varied size, and 

 therefore presumably of varied age, a short segment is to be .seen between the 

 backwardly projecting lolie of the epimera of the last segment of the mesosome. This 

 segment is very often undeveloped or cuncealeil. Ant)ther segment has a peculiar 

 postiM-ior Itorder ; it pas.se3 across the mid-dor.sal line and at some little distance from it 

 it forms an angular projection backwards, and then on in a slightly sinuous line to the 

 epimeron. Just outside the angular projection two lines pass forward in a cre.scentic 

 manner to lo.sc thcm.sclves after a short cour.se. This proves the segment to be 

 incompletely divided into three. 



The urosome is as long as the five posterior segments of the mesosome ; it tapere 

 posteriorly, and the lateral margin is inflected so that it terminates as a spout with an 

 oblique orifice, and the plcopoda lie in a sort of pocket. The inflected margins are not 

 fused distally, a narrow groove separates them. 



The uropoda are conspicuous but not very large, not reaching the extremity of the 

 urosome. They arise from a notch near its anterior border and possess a stout 

 protopocbte ; the cxopodite is much smaller than the endopodite, of which the inner 

 half is much thickened ; both are lanceolate in form. The endopodite is larger in 

 proportion and somewhat raoi'e angular in some of the smaller specimens. 



The antenn;e arc completely ventral in position, the first lies naturally in a groove 

 between the cephalosome and the epistome. 



The first antenna has a very stout peduncle of three joints. The first is as long as 

 the other two together, very stout and bent at the base ; the .second is ecjually stout 

 but .short ; and the third is much more .slender and a little longer ; the flagellum 

 consists of six joints. 



The second antenna is larger than the first and rises quite close to and uuderneath 

 it ; the peduncle is three-jointed, the three progressively increasing in length ; the 

 flagellum comprises eleven joints, each of which, except the first, has a couple of tufts 

 of speciali.sed setie on the ventral surface. 



The Imccal ma.ss is rather prominent, and tjie epistome is triangular in shape with 

 a wide and shallow piece taken out of the base. 



The mandible is strong, curved and tapering, but with a sinuous margin ; the 

 cutting edge is retluced to a l>lunt point, bifid, to form two strong but short teeth ; 

 on the inner side and a short distance from this is a group of stout .spines. The molar 

 process is stout, rather long, and forms a broad cutting edge. 



There is a three-jointed palp, the first two joints of which are subequal, the third 

 is shorter. The second has half-a-dozen strong spinous setaj distally on its inner 

 margin, and the third has a .series beginning about one-third of its length, at first 

 small, but the distal ones are very long. 



The first pair of maxilhe consists of two long slender lobes united at the ba.se 

 by a connecting piece ; fully one-half of the inner lobe is imbedded in muscle ; the 



