ANTARCTIC ROTIFERA 45 



did they die when alternately thawed and refrozen at weekly intervals for several 

 months. They lived for a month in sea-water and in a much more saline solution, and 

 became active again immediately on being transferred to fresh water. They were 

 dried while in the Antarctic by exposing to the air till all the ice passed off by ablation, 

 ' and were then conveyed by a long voyage through the tropics to England, where they 

 revived within an hour of being moistened and could be seen alive in London a year 

 after they were collected. 



In England they were subjected to a temperature of 78 Cent, for many hours, 

 by Mr. J. H. Priestley, of Bristol, and survived. 



Philodina antarctica, sp. n. (Plate X., Figs. 5a-5c) 



Specific characters. Large, elongate : corona of moderate breadth, wider than 

 the prominent collar, discs with central papilla?, each bearing several fine setae ; 

 antenna long : teeth 2/2 : foot four-jointed, long, slender ; spurs with broad triangular 

 basal portion, and narrow apical portion of about equal length (Fig. 5b) ; last joint 

 of foot short, dorsal toes nearly as large as the ventral ones : pale brown eyes. 



Detailed description. The size is variable. The shortest measured was 380 /* in 

 length, in the feeding attitude, and with the foot well drawn in. The longest 

 measured 714 n, fully extended, creeping. In a large example the diameter of the 

 corona was 96 n, of the collar 73 M, of the neck 60 p., of the trunk 106 n : the length 

 of the spur was 30 /x. 



The stomach is of a deep ruby-red colour, the anterior part of the body of a 

 faint brown, and the foot clear and hyaline. The longitudinal folds of the trunk 

 are deep at the sides and shallow on the back. The discs are separated by a space 

 equal to half the diameter of a disc. Into this come the low rounded lobes terminat- 

 ing the collar. They are slightly separated, and the part between is convex. The 

 collar appears two-lobed in dorsal view, and is distinctly marked off from the pedicels. 

 The rostrum is short and broad. The length of the antenna is equal to the diameter 

 of the neck segment bearing it. The reproduction is unknown. Neither eggs nor 

 embryos were ever seen. The yolk mass has the eight nuclei usual in the order. 

 The vibratile tags were not detected. 



It was an extremely difficult animal to study, on account of its restless disposition. 

 It went wriggling and twisting and creeping about, often stopping to feed for a 

 moment, but never still. There were no narcotics available when it was first found 

 in considerable numbers, and it afterwards proved to be a rare species, and very 

 uncertain in its occurrence. For this reason no photographs were obtained, and 

 no specimens could be preserved. 



Habitat. Among plants in the ice of several lakes at Cape Royds and Cape 

 Barne. It was never got except by thawing the ice of the lakes. Most of the lakes 

 in which it lived did not melt in either of the two summers we spent in the district. 



Affinities. Belonging also to the central group of species, there is little in its general 

 proportions and characters to distinguish it from several other species. It is more 



