ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 237 



of forms are derived from the benthos. The pools were either (1) 

 traversed by a considerable stream ; (2) supplied by bottom springs or 

 by small streams from adjacent springs ; or (3) supplied by overflow 

 from the river Stour. An analysis of the collections is set forth in 

 tabular form. The following points of interest are emphasized : — 1. The 

 presence of Bacillarieae other than Asteriondla is probably due to the 

 occurrence of weeds, through which the plankton-net was unavoidably 

 drawn. 2. The presence of Pandorina and Eiidorina in the plankton 

 appears to be correlated with comparative purity of water. 3. The 

 presence of Microcystis seruginosa and other Myxophyceae seems to 

 indicate contamination. It occurred abundantly in those pools which 

 were exposed to contamination from a village or from house-drainage. 

 Another contaminated pool contained enormous quantities of Aphani- 

 zomeno?i Flos-aquae. 4. Two of the pools had a predominant Proto- 

 coccales flora. One of these is supplied by springs, and the other is 

 derived from the River Stour. The latter contained Crucigenia remi- 

 formis, C. apiculata, Scenedesmus RacihorsTcii, and Dictyosphaerium pid- 

 chellum. 5. Peridinieae occurred in two of the pools, where there was 

 but slight contamination. 



A noteworthy feature was the number of algse that was either very 

 rare or not commonly found, such as Microcystis ochracea Forti, Ftero- 

 mo7ias aculeata Lemm., Scenedesmus RaciborsTcii Wolos., Oocystis parva 

 W. & G. S. West, Crucigenia apiculata Scbmidle, Tetrastrum staurogenise- 

 forme Chodat, Oeminella interrupta Turpin, Geratium Hirundiaella 

 Schrank. Two new species are described. 



French Peridiniese.* — J. Pavillard publishes the result of his re- 

 searches on the Peridinieae of the Gulf of Lions, which includes a 

 systematic list of the Peridinieje collected by himself. To most of the 

 species notes are appended on their morphology or geographical distri- 

 bution. Eleven new species, one new genus (Pachydinium), and some 

 new varieties are described. 



Swedish Plankton-algae.f — E. Telling continues his studies of 

 Swedish plankton, and in the present contribution describes a new genus 

 of Protococcoidese which he calls Tetrallantos. It is most closely allied 

 to Dimorphococcus, and has affinities with Schmidleia and Schrmderella. 

 It was found in a pond of over 1 m. in depth in the vicinity of Skara, 

 a town in Gotland. Here the author collected an abundant material 

 of plankton in the summer of 1915, consisting almost entirely of Pro- 

 tococcoideas, Desmidiace^e, and Flagellatas. Species and varieties new 

 to Sweden are recorded, as well as the novelties Tetrallantos Lagerheimii 

 and Trachelomonas Hystrix. 



Phytoplankton from the Indian Ocean. | — G. B. de Toni and 

 A. Forti report on a collection of phytoplankton collected by the 



* Trav. Inst. Bot. Univ. Montpellier et stat. zool. Cette, M6m. iv. (1916) 70 pp. 

 (3 pis.). See also Nuov. Notar., xxviii. (1917) pp. 123-4. 



t Svensk. Bot. Tidskr., x. (1916) pp. 59-66 (14 figs.). See also Nuov. Notar., 

 xxviii. (1917) pp. 121-2. 



X Mem. R. Istit. Veneto Sci. Lett. Art., xxix. No. 1 (1916) 33 pp. (3 pis. and 

 figs, in text). 



