WATERLIME GROUP. 403* 



little beyond the margin of the carapace, and are usually not visible 

 from above. The first three pairs have a gradually increasing length : 

 the fourth pair is about one-fourth longer than the third, and more 

 slender. The fifth pair, or natatory feet, when bent downwards at the 

 sides, reach to the fifth or sixth articulation of the body. The distal 

 margins of the smaller of these articulations are prolonged on their 

 anterior edges into sharp angular processes ; the last joint is broadly 

 ovate, and the terminal notch and palette very minute. 

 Surface in some parts faintly marked by imbricating scales, and the 

 carapace is finely granulose. * ■" 



This species differs from the following, both in size, and in the proportions of the 

 carapace and other parts of the body, as will be seen by comparison of the figures. 



The postoral plate, which has a general oval form, is narrower in front, with the 

 sides regularly curving for a little more than one-third the length, at which point is 

 the widest part of the plate : below this the sides are a little more straight, and the 

 lower end is abruptly rounded. 



The E. remipes and E. lacustris have usually been confounded by authors, and 

 but a single species has generally been recognized. 



PLATE LXXX. 

 Fig. 1. A young individual, dorsal side. 



Fig. 2. A young individual, ventral side ; showing the anterior feet, the post-oral plate, with 

 the articulations of all the parts nearly entire. 



Fig. 3. A young specimen, showing the upper side of the body, which is entire, except the 

 posterior spine and a part of the anterior feet. 



Fig. 4. A large individual of nearly the full size to which the species attains, lying upon its 

 back, and having the lower or ventral side of the articulation removed ; showing 

 therefore the inner side of the carapace, and the articulations of the thorax and 

 the abdomen. The anterior feet are partially preserved, and the swimming feet 

 are entire, the lower side being shown. At s .5 is the line of the suture by which 

 a triangular piece is attached to the sixth joint, forming the fixed ramus of the 

 chela, and over the upper surface of which the free extreme joint moves. The 

 articulation of these parts with the body is not clearly shown, from the incom- 

 pleteness of the specimen, the parts to which they were attached having been 

 removed. 



Fig. 5. An individn.il preserving more than usual convexity of body. The head and eyes are 

 very perfect : the anterior feet are lost, but the swimminz feet are well preserved 

 in all their parts, and the indented extremities are strongly marked. In the 

 contractiou of the extreme joint, the fixed branch of the chela below is nearly 

 covered. In comparing the swimming feet in fijijures 4 and 5, it will be observed 

 that in the former the lower side, and in the latter the upper or dorsal side, is 

 seen. 



Fig. 6. A small carapace preserving the eyes. 



