FRESHWATER CRUSTACEA OF TASMANIA. 89 



Cyclops albicans, sp. n. (PI. 16. figs. 8-12.) 



The head-segment is broad and blunt ; the succeeding segments have rounded edges, 

 which do not project laterally to any extent. 



The uropods are about as long as the last two abdominal segments. They are 

 furnished each with four terminally placed setae, of which the innermost is much longer 

 than the outermost, but none of them are as long as the abdomen (PI. 16. fig. 12). 



The first antenna, which is as long as the first two segments of the cephalothorax, 

 consists of 17 joints. The terminal segments are without a row of spines or hyaline 

 membrane (PL 16. fig. 12). 



The first swimming-leg (PL 16. fig. 9) has both branches consisting of three joints, and 

 so have the succeeding swimming-legs. The last two joints of the inner ramus of all 

 but the first pair have their internal margin serrated (PL 16. fig. 10). 



The rudimentary fifth pair of limbs consist of two distinct joints ; the terminal joint 

 carries a plumose seta at its tip, and on its inner margin a serrated spine nearly as long 

 as the seta and situated on the inner margin near the tip. The basal joint carries a 

 fairly long seta on its external border (PL 16. fig. 11). 



Length *8 mm. 



Colour. Very pale green or white. 



Occurrence. In the plankton of the Great Lake, and also in many small ponds, widely 

 distributed. 



Cyclops dtjlvertonensis, sp. n. (PL 17. figs. 1-3.) 



The head-segment is broad and blunt, but equal in length to the rest of the thorax. 

 The thoracic segments have their hinder edges distinctly produced and overlapping the 

 segments behind them. 



The uropods are rather longer than the last two abdominal segments. They are 

 furnished each with four terminal setae, the innermost being very slightly longer than 

 the outermost, and the longest is as long or longer than the abdomen (PL 17. fig. 3). 



The first antenna ( ? ), which consists of 12 joints, is about as long as the head- 

 segment. The terminal segments are without a row of spines or hyaline membrane. 



The first swimming-leg has the inner ramus 2-jointed and the outer 3-jointed, the 

 basal joint being rudimentary. The succeeding legs have both rami 3-jointed, but 

 without any serration on the inner ramus. 



The rudimentary fifth pair resemble closely that of the foregoing species. 



Length '5 mm. 



Colour. Dark green. 



Occurrence. Among thick weed in Lake Dulverton. 



