ZOOLOGY AND BOTANY, MICEOSOOPY, ETC. 1013' 



formed the palmelloid colonies, in wbich condition Chlorothecium may 

 multiply itself non-sexually without producing zoogametes. 



Reproduction of Nephrocytium.*— M. P. A. Dangeard has observed 

 the hitherto unknown mode of propagation of Neplirocytium Agardkiamm, 

 by the formation of four or eight colonies within the membrane of the 

 mother-colony, which they finally rupture. They are entirely unprovided 

 with cilia. 



TrocMscia and Tetraedron.j — Prof. A. Hansgirg proposes to restore 

 Kiitzing's generic name TrocMscia for the AcantJiocladus of Lagerheim 

 CGlochiococcus De Toni), dividing it into the three sections Acanthococcus, 

 Dictyococcus, and Kymatococciis ; as also Kiitzing's Tetraedron (Astericium 

 Corda, Polyedrium Nag., Cerasterias Reinsch), this again consisting of 

 two sections Polyedrium and Pseudostaurastrum, the latter including 

 Ealfs's Slaurastrum enorme. 



Polyedriacese.l — Herr P, F. Eeinsch proposes to establish under 

 this name a new family of Palmellacese, distinguished by consisting of 

 single cells, with periphery either regularly geometi'ical or varying 

 between all degrees of lobing ; the number of nuclei is often consider- 

 able, and the cell-wall thick. The family is divided into two sub- 

 divisions : Polyedriese with simple, Cerasteriese with compound colonies. 

 Each is composed of two genera, the former of Polyedrium Nag. (ex 

 part.) and Closteridium n. gen., the latter of Cerasterias Eeinsch and 

 Thamniastrum n. gen. ; and the total number of species is 27. 



Closteridium is distinguished by its solitary free-swimming sub- 

 cylindrical or semilunar cells, each pole armed with a single sjiine. 

 The membrane is thin, but thicker towards the poles, and prolonged 

 into the spine. The cytoplasm is coarsely granular, and contains large 

 chlorophyllous granules. The species have the appearance of a 

 Closterium. 



In Tliamniastrum the cells are solitary, free-swimming, and usually 

 composed of six branches arranged in the form of an octohedron. The 

 branches spring from a common centre, and themselves branch re- 

 peatedly dichotomously or trichotomously, these secondary branches are 

 ultimately bifurcate ; the total number of secondary branches may 

 amount to from 100 to 180. 



Bacillus living at a temperature exceeding 70° C.§ — ^This microbe 

 {B. thermophilus) which has been cultivated by Dr. P. Miquel, is 

 characterized by being viable at a temperature above 70° C. The 

 author's method of obtaining it was as follows : — 



In an oil-bath kept at a temperature of 69° are placed several vessels 

 containing sterilized slightly alkaline pepton-bouillon. When the 

 temperature of the bouillon reaches 69°, a drop of sewer (or other dirty 

 water) is allowed to fall into each of the tubes. In twenty-four hours 

 all the vessels have become cloudy from the presence of B. tJiermopJiilus. 

 The bath is then raised to a temperature of 71° and fresh bouillon tubes 

 placed in it. These new tubes are inoculated with a small drop of the 

 cultivation, and so on to the fourth generation. Then in order to be 



* Bull Soc. Linn. Normandie, i., 1886-7(1888) pp. 196-8. 



t Hedwigia, xxvii. (1888) pp. 126-82. 



1 Notarisia. iii. (1888) pp. 493-516 (5 pis.). 



§ Ann. de Micrographie, i. (1888) pp. 1-10. 



