SOME EOTIFERA FROM SPITSBERGEN. 331 



rotifer that there was none left for the contractile cloaca to 

 deal with. 



A day later the rotifer was distinctly weakened, and as I was 

 temporarily leaving home I essayed to make a preparation 

 showing the parasite in situ, but did not get a satisfactory result. 



The parasite may be shortly described as an animal apparently 

 belonging to the Vermes, having a distinct head, a long tube- 

 like unsegmented central body and a distinct terminal segment. 

 Whether it is identical with any form already known has not 

 yet been ascertained. All internal parasites hitherto recorded 

 for rotifera have been either very minute protozoa, ajgae, 

 amoebae, or bacteria. This form is very much larger than any 

 of these, and of much more specialised structure. It had pre- 

 viously been seen by me in a specimen of the same rotifer from 

 Perranporth (Cornwall) and in another from KiUin (Perthshire). 

 The host is almost exclusively an inhabitant of ground mosses 

 and is a very hardy and long-lived species, usually of distinctly 

 reddish- yellow colour. 



This second infected individual from Spitsbergen had another 

 very interesting abnormality which may or may not be connected 

 with the presence of the parasite. 



In this species and in one or two other large forms, the fluid 

 of the body cavity contains numerous very fine particles which 

 have been regarded as blood corpuscles. In this individual I 

 observed among such particles some larger particles, about a 

 dozen in all, which, like the small, were driven hither and thither 

 by every change of position of the rotifer. Of these larger par- 

 ticles some seemed longer than broad, others appeared tri- 

 angular in form. I presently found that the former were identical 

 with the latter, and simply represented their lateral aspect. 

 The triangular forms were accordingly flattened tablets, each 

 side about 5-6 jx long, with approximately equal angles (fig. 6d). 



Tardigrada. 



Although water-bears were found in several gatherings of 

 moss, only a very few individuals were revived, representing two 

 distinct species. One of these was a Macrobiotus, which I did 

 not attempt to identify more closely. The second proved to be 

 Echiniscus Spitsbergensis Scourfield, a species first discovered in 



