Victorian Fresh-ivatcr AmpldiJoda. 227 



posterior margins of each minutely serrate. The third 

 peraeopoda considerably shorter than the fourth, and the 

 fourth slightly longer than the fifth, the coxal lobe of the fourth 

 deeply produced, and its hind margin bearing five spinules. 

 First uropoda reaching slightly beyond the end of the second, 

 peduncle much longer than rami, with few spines ; the second 

 ■with peduncle of subequal length to its rami, inner ramus 

 slightly longer than outer ; the third short, peduncle stout, 

 longer than its ramus, which is minute, conical, apically rounded, 

 and tipped ))y a few long setae. Telson entire, thick at the base, 

 convex above, the end wide, almost straight, and bearing four 

 spinules, lateral margins convex. 



Female. — .Smaller in size but of similar form to the male except 

 in the second gnathopoda, which are subequal in form to the first. 

 The second is longer, the propodus slightly larger, and, compared 

 with the first gnathopod of the male, the propodus is similar in 

 armature, but longer, the palm narrower, transverse, and the 

 margin slightly convex. The carpus also is longer and bears 

 about thirteen finely feathered setae. 



Colour. — When alive pale green. 



Length. — Largest <? 8 mm. Largest ? 7'25 mm. 



Occurrence. — Very common in the following lagoons along the 

 valley of the River Yarra and its tributaries, Fernshaw, Christ- 

 mas Hills (collected by C. Barber), Heidelberg, East Kew, Mel- 

 bourne Botanical Gardens, and Elwood Swamp. 



Distribution. — Lake Petrach, Tasmania. Altitude 2900 feet 

 (collected by Professor Baldwin Spencer). 



Remarks. — Hyalella appears to have no conspicuous characters 

 at variance with Hyale except in respect of the telson which is 

 entire, whereas in Hyale it is cleft to the base. The species of 

 the latter genus are mostly marine inhabitants, and so far those 

 of Hyalella have ovAy been recorded from the fresh-waters of 

 North and South America and New Zealand. The present 

 species is undoubtedly congeneric with H. mihiwaka, Chilton, 

 found in mountain streams in New Zealand, but is easily 

 distinguished from it by the narrower side-plates, the shape of 

 the hands, the longer segments of the urosome, and by the 

 peduncle of the terminal uropoda being distinctly jointed to its 

 segment, and not apparently coalescent, as in that species, also 



