TARDIGRADA: AUSTRALIA 137 



of these have some spines on the body which may be homologous with the lateral and 

 dorsal processes, especially two at the posterior extremity which appear to be the 

 most constant, and are probably homologous with seta e of Echiniscus. Even in the 

 genus Macrobiotus certain species (M. dispar, M. aculeatus, and perhaps the group of 

 species related to J/. tuberculatus) have dorsal processes in pairs, which may be 

 homologous with those of Echiniscus. 



Oreella is nearer to Echiniscus than any of_the other genera. It has all the ten 

 processes occupying the same positions, and only slightly modified in detail. The 

 teeth, pharynx, and claws are all as in Echiniscus. The only important difference is 

 the lack of the armour-plates. 



GENUS Milnesium, Doyere (2) 

 Milnesium tardigradum, Doyere (2) 



Common in all the districts visited, in New South Wales and Queensland. 

 Milnesium is the most thoroughly cosmopolitan of all Tardigrada. 

 In the Australian Alps a skin was found which contained ten eggs, each measuring 

 104 n in length. 



GENUS Macrobiotus, Schultze (42) 

 A : SPECIES WHICH LAY ROUGH EGGS, FREE 

 Macrobiotus hufelandii, Schultze (42) 



The commonest Tardigrade here as in most other places. Found in all the 

 localities visited ; eggs equally common. 



Macrobiotus echinogenitus, Richters (27) (Plate XVIII. Fig. 30) 

 At Katoomba in the Blue Mountains, elevation 2000 to 3000 feet. 



Macrobiotus areolatus, Murray (19) 



At Katoomba in the Blue Mountains ; only eggs seen. This species, which was 

 regarded as a variety oi'M. echniogenitus, is described as a species among the Canadian 

 Tardigrada in this paper, as in Canada material was got for a study of the egg, the 

 young, and the adult. It can be identified from the egg alone. 



Macrobiotus harmsworthi, Murray (19) (Plate XVIII. Fig. 31) 



In the Australian Alps, near Mount Kosciusko, altitude 5000 to 6000 feet. Not 

 to be identified with certainty from the adult alone or from the egg alone. It is 

 necessary to find an egg containing a well-grown young, or an adult with ripe eggs 

 in the body. In this instance the young was found in the egg. 



BRIT. ANTARCT. EXPED. 1907-9. VOL. I. T 



