ZOOLOOY AND BOTANY, MICROSCOPY, ETC. 73 



Algological Notes.* — N. Wille publishes a continuation of his 

 notes, founded on the results of his studies at Tatihou and Cherbourg in 

 ,1 uly and August 19U9. He records the finding of PseuiUndoclonium 

 submarinum Wide on the wood of the quay at St. Vaast-la-Hougue, and 

 describes certain points in its growth and anatomy. He found it sub- 

 sequently at Tatihou : it has hitherto only been recorded from northern 

 seas. Ulothri.r pseudoflacca, described by the author from Drobak in 

 Norway, was found by him on Fucus spiralis at Cherbourg. It has 

 hitherto been considered an arctic species. A doubling of the filament 

 is described here, occurring as a freak. A new species of Slereococcus, 

 S. Malardii, was found on the quay wall at St. Vaast-la-Hougue, and 

 is described and figured. The author next deals with a very interesting 

 endozootic Chlorophycea which grows in the sponge HaHckondriapanicea 

 Johnst. It was found not only among the exterior parts of the sponge, 

 but also in the interior, and consists of long unbranched filaments which 

 are sometimes straight, sometimes intertwined. After a full description 

 of the alga, the author states his views on its systematic position. He is 

 inclined to think that it is not a new genus as might be supposed, but 

 merelv a Yerv much changed form of Rhizoclonium Kemeri Stockm. 

 He discusses the points for and against such an assumption, a point 

 which can only be settled by further study of fresh material. The next 

 note describes a sample of plankton from St. "Vaast-la-Hougue, taken 

 with a view to testing whether marine plankton is always poor in the 

 summer months, as has been supposed. The sea was found to contain 

 large quantities of sand-grains, and the plankton was purely a coast- 

 plankton. The small number of species is, in the author's opinion, 

 probably accounted for by the large quantity of sand-grains which, in 

 sinking to the bottom of the sea, carry with them the light floating 

 plankton. In the final note, a new species, Goccomyxa Gorbierei, is de- 

 scribed. It was found growing in a glass-house in Emmanuel Liais 

 Park, Cherbourg, forming a green covering to some woodwork. The 

 points of distinction between this species and the others of the genus 

 are given. 



Studies on the Conjugatse.t — R. Chodat writes on the copulation of 

 Spirogyra quadrata var. mirabiUs, which takes place in two ways, called 

 respectively " xenogamic " (conjugation of distinct filaments), and 

 " pedogamic " (conjugation of contiguous cells of the same filament). 

 In the former mode (described as " copulation scalarif orme ") the fila- 

 ments are differentiated into male and female ; and Chodat gives a 

 detailed account with figures. In " pedogamic " two contiguous cells of 

 one filament unite after perforation of the septum that divides them. 



Diatoms.J — A. Forti continues his studies on Diatoms, publishing 

 three contributions to the series. The first (No 9) deals with Gera- 

 taulus polymorph us and C. orbicularis sp. n., with their systematic 

 revision ; and discusses the true nature of C. thermalis Ralfs. The 

 varieties and forms of each species are carefully described, together with 



* Nyt. Mag. Naturvidensk., xlviii. (1910) pp. 281-306 (2 pis.). 



t Bull. Soc. Bot. Geneve, ser. 2, ii. (1910) pp. 158-67 (figs.). 



% Atti R. 1st. Veneto Sci. Lett. Art. lxix. (1910) pp. 1249-1317 (9 pis.). 



