Chilton. — Additions to the Neiv Zealand Crustacea. 69 



Akt. II. — Further Additions to our Knowledge of the Neiv Zealand Crustacea. 



By Charles Chilton, M.A. 



[Read before the Philosophical Institute of Canterbury, 1th September, 1882.] 



Plates I.-III. 



BEACHYUEA. 



Hymenosoma lacustris. 



Elamena(?) lacustris, Chilton. (Trans. N.Z. Inst., vol. xiv., p. 172.) 

 This species was described from a single specimen, a female. I have since, 

 through the kindness of Professor Hutton, received seven others, all males, so 

 that I am now able to describe it more fully and to refer it to its proper genus. 



In the Catalogue of the Stalk- and Sessile-eyed Crustacea of Australia 

 Mr. Haswell has replaced the genera Hymenicus and Halicarcinus by 

 Leach's original genus Hymenosoma ; and my species will also come under 

 this genus as it is defined in Mr. HaswelTs catalogue. Its name will 

 therefore be Hymenosoma lacustris. 



Specific description : — Carapace nearly circular, rather broader than 

 long ; flat, naked, or with a few scattered hairs. Eostrum broad, strongly 

 depressed, its upper surface concave from side to side, extremity in the 

 form of an obtuse angle. Antero-lateral margins of the carapace with two 

 obscure teeth. Chelse of male small, propodos only slightly broader than 

 the carpus, hairy. Ambulatory legs somewhat densely covered with long 

 hairs, tarsi long, slender, compressed, densely-haired. Last pair of legs 

 somewhat shorter than the preceding. Abdomen of male of five joints 

 subequal in length, third rather narrower than the first and second, fourth 

 nearly as wide as the third, last broadly rounded at the end ; margin 

 fringed with very short bans, some longer ones being scattered on the sur- 

 face. Abdomen of female with a slight median ridge along its whole length. 



Hob. Lake Pupuke. [Fresh water.) 



The hairs on the legs and carapace appear to be somewhat variable. 



The third (external) maxillipedes are shown in pi. L, fig. 2 a. On them 

 are found setse of several kinds ranging from the ordinary plumose setae (c) 

 to others strongly serrated on each side (b). 



This species is remarkably near Hymenosoma australe, Haswell, from Port 

 Phillip. From this, however, it differs in the chelas of the male which are 

 small, while in H. australe they are " extremely large." 



ISOPODA. 

 Genus Scutuloidea, (novum). 



Generic description : — Body not very convex. Pereion much broader 

 than the cephalon, increasing regularly in breadth up to the fourth segment 

 and then decreasing again. 



