C. F. ROUSSELET ON RATTULUS COLLAEIS. 267 



In swimming the animal moves slowly, as if the small ciliary 

 wreath were not powerful enough to move the comparatively 

 large body, and I always found it at the bottom of my tanks 

 among the sediment. 



Length, total, with toes, J- in. (0-317 mm.); of body alone, 

 T |o in. (0-212 mm.) ; of toes alone, -^h" in - (°' 105 mm.). 

 Habitat : Sandhurst, Berks. 



I take this opportunity to describe two Rotifers which I 

 found in Germany in September of last year, and which, 

 although not new to science, have not yet been found nor figured 

 in England. 



Polyarthra platyptera, v&r. euryptera (Wierzejski), (Fig. 2). 



I obtained this large and fine Polyarthra in abundance in 

 a small forest lake situated at Dornholzhausen near Bad- 

 Homburg, associated with another stranger to England : 

 Mastigocerca setifera (Lauterborn). This Polyarthra is 1 well- 

 marked variety of, and much larger than our common P. 

 platyptera. Its chief peculiarity consists in having very 

 broad, leaf-like paddles, instead of the narrow blades of 

 platyptera ; there are six paddles on each side in two groups 

 of three, which evidently are much more effective in propelling 

 the animal when danger is near. Otherwise the structure and 

 anatomy of both animals are alike, but the female eggs of 

 euryptera are much more pointed at one end, while in the 

 common form they are regularly oval. Fig. 2 shows a dorsal 

 view with a cluster of small spherical male eggs, and Fig. 2a a 

 side view with a large female egg attached. This species was 

 first discovered by Professor A. Wierzejski in Galicia, and 

 figured by him in his work, " Rotatoria Galicyi," in 1893. Its 

 size is T -J in. (0-181 mm.). 



I am indebted to Mr. F. R. Dixon-Nuttall's kindness and 

 facile pencil for the very good figures of this difficult animal ; 

 they were drawn from my mounted specimen, and a slide of 

 them will be placed in the cabinet of the Club. 



ScMzocerca diversicornis (Daday), Fig 3. 



I found this fine and very peculiar Rotifer of the family 

 Brachionadae living in a large fountain basin in the gardens of 



