94 SUMMARY OF CURRENT RESEARCHES RELATING TO 



distinguish between these fertile branches and the branches which occur 

 in large numbers on the carpogonium-branch before impregnation, and 

 which resemble paraphyses. 



Microspora.* — M. E. De Wildeman contends that this genus, formed 

 by Thuret, should be again sunk in Conferva. The character on which 

 the author relied for establishing the genus, the peculiar way in which 

 the cell-wall behaves previous to the emission of zoospores, resembling 

 the process called by Gay "encysting," f is not a good generic character, 

 but is rather a peculiar condition which occurs in a number of different 

 genera of algae. 



Some points in Diatom-structure. :j: — From observations made with 

 a 1/12 in. oil-immersion lens, Mr. T. F. Smith has come to different 

 conclusions in some respects from those of Messrs. Nelson and Karop,§ 

 as to the structure of the valve of Coscinodiscus asteromphalos. He objects 

 to the term " double structure,'' if it implies that the two areolations are 

 nearly on the same plane. As a matter of fact, each single disc of this 

 diatom has three thicknesses of structure, each differing from the other. 

 There is first the outer membrane, next a layer of hexagonal cells, and 

 then an inner plate of so-called eye-spots. In C. centralis, what 

 Nelson and Karop have figured as fine perforations are, according 

 to Mr. Smith, little bosses standing out from the outer membrane. A 

 similar structure is attributed by the author to Aulacodiscus Kittonii and 

 Triceratium favus. He does not commit himself to an opinion whether 

 the eye-spots have, in all cases, a closing membrane, but he thinks it 

 clear that they have in some. 



In a later paper,|| Mr. Smith admits that the diatom described by 

 him as Coscinodiscus centralis is not the same species as that referred to 

 under this name by Nelson and Karop. 



Deep-sea Diatoms.1T — Abbe Count F. Castracane adduces new evi- 

 dence of the depth of the ocean at which diatoms can live, from an 

 examination of the contents of the stomach of Echini and Holothurise, 

 dredged up from a depth of 2511 to 5274 metres. These contain the 

 remains of diatoms belonging to the genera Synedra, Bhizosolenia, &c, 

 in such a condition that the author contends they could only have been 

 consumed in the living state. 



Fossil Marine Diatoms from New Zealand. ** — Messrs. E. Grove 

 and G. Sturt publish the results of their examination of a fossil marine 

 diatomaceous deposit from Oamaru, Otago, New Zealand. A very large 

 number of new species are described. 



Wolle's ' Fresh-water Algae of the United States.' ff — This work is 

 supplementary to the Rev. F. "Wolle's well-known ' Desmidieas of the 

 United States,' and comprises all the remaining families of fresh-water 

 alga3, except the diatoms. It includes also nine new plates of desmids. 

 The Algae treated are arranged under three classes : Khodophyceae, 



* CK. Soc. R. Bot. Belgique, 1887. pp. 92-6. t See this Journal, 1887, p. 277. 



% Journ. Quek. Mier. Club, iii. (1887) pp. 125-30. 



§ See this Journal, 18S6, p. 661. |j Tom. cit., pp. 163-6 (1 pi.). 



^ Atti Accad. Pontif. Nuovi Lincei, xxxviii. (1886) pp. 46-7. Cf. this Journal, 

 1885, p. 498. ** Journ. Quek. Micr. Club, iii. (1887) pp. 131-48 (5 pis.). 



ft Wolle, Bev. F., ' Fresh-water Algae of the United States, exclusive of Dia- 

 tomacese,' 2 vols., 364 pp., and 151 pis.. Bethlehem, Pa., 1887. 



