ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 399 



individuals, in a kind of nest hollowed in the detritus which floats on 

 the surface of the water. From time to time an individual goes out, 

 makes a short excursion in the neighbourhood, and returns to its home. 

 Those which remain in the nest are almost immobile, making only a 

 slow rotatory movement, comparable to that of encysted Infusoria. The 

 body is flexible, but not contractile, and its form varies considerably 

 with the state of repletion of the individual. The moutli has the form 

 of a long cleft, which is bordered on either side by a cnticular thicken- 

 ing, and it has a considerable power of comparatively rapid distension. 

 The arraDgement of the strias of cilia is always more or less spiral, but 

 differs a little at either pole. 



The author also describes a new species of Opalina, which he calls 

 0. cerehriformis, on account of the presence on its convex surface of 

 a deep groove, and the arrangement of its strise of cilia, which give a 

 twisted appearance to the whole mass. 



Holotrichous Infusoria parasitic in White Ants.* — Mr, W. J. 



Simmons finds that the lower portion of the alimentary canal of the 

 white ant teems with parasites. Among these there is a holotrichous 

 infusorian which changes constantly in form. No name is given to the 

 creature, and the author seems to be in doubt as to the morphology of 

 some parts of its organization. 



Parasitic Monad.j— Herr W. Zopf gives an account of the de- 

 velopment of a new pleosporous fresh-water Monad, which he calls 

 Pulysporella J Kutzingii ; it was found parasitic in various Algae. The 

 lasting spores or sporocysts are distinguished from those of other Monads 

 by being pleosporous (4, 8, 16 lasting spores) ; the form of the cysts is 

 adapted to the cells of their hosts. The investment is simple as com- 

 pared with that of other Monads. The zoocysts are generally somewhat 

 smaller than the sporocysts, and the zoospores make their way to the 

 exterior, but the direct infection of new algar cells has not yet been 

 observed, but it may be considered as certain that they give i*ise to 

 Amoebse ; these grow by the ingestion of food. When sufficient has 

 been taken in the Amcebse draw in their processes, become rounded 

 and encysted. The further development of the contents varies according 

 as the cyst shall give rise to a zoocyst or a sporocyst. The development 

 of either is by successive fission of the protoplasm. These organisms 

 belong to the family Pseudosporete. 



Dino-Flagellata.§— M. E. Penard treats especially of the structure 

 of the genus Geratium, which he regards as belonging to the vegetable 

 rather than to the animal kingdom. He describes three modes of re- 

 production, viz. : — (1) By internal embryos. In the summer he found 

 in some individuals from one to four elliptical cells, with nucleus, chloro- 

 phyll, and eye-spot. These escape from their inclosing envelope, are 

 either motile or immotile, according to the rigidity of the membrane 

 which envelopes them, become encysted, and pass through a resting 



* Tlie Microscope, is. (1889) pp. 53-5. 



t ' Untersuchungen iiber Parasiten aus der Gruppe der Monadinen,' fol., Hallo, 

 1887, 39 pp., 3 pis. See Bot. Centralbl., xxxvii. (1889) pp. 206-8. 



X At the end of the abstract the new generic name is said to be Pleosporella. 



§ ' Coutrib. a I'etudo dcs Diuo-Flagclles,' Geueve, 1888, 43 pp., 3 pis. See Bot. 

 Centralbl., xxxvii. (1889) p. 131. 



