744 SUMMARY OF CURRENT RESEARCHES RELATING TO 



rather scarce. April : green algae, both desmids and Protococcoideae 

 dominate ; diatoms of less importance ; blue-green algse rather scarce. 

 October and November : Myxophyceae dominant, but both green algse 

 (especially Botryococcus Braunii) and diatoms (Melosira nyassensis and 

 Surirellae) subdominant. Plankton very rich in species and individuals. 

 The author makes critical remarks on certain species of Per idini ales, 

 Bacillariales, and Myxophyceas and Chlorophyceae. M. Agassizii is 

 described and figured as a new species. 



Green Algse of North America.* — F. S. Collins publishes an account 

 of the green algse of North America, from the Arctic Ocean to the 

 Isthmus of Panama, including the West Indian Islands. In the green 

 algae are included not only the Chlorophyceae, but also the small class 

 of the Heterokontse, but the Desmidiaceae and Oharacese are omitted. 

 Under each species is a concise description, with a record of the localities 

 in which it has been found. Reference is also given to the original 

 publication of the binomial, and to some good figure or plate, and where 

 a specimen of the species in question has been published in some ex- 

 siccatae, reference is also made to that. In the plates there is at least 

 one figure for each genus, and in most cases these are taken from standard 

 works. A key is given to the species of each genus. In an introduction 

 the author describes methods of collecting and mounting the various 

 kinds of algae, different types requiring different treatment. 



North- American Fresh-water Algae .f — 0. Borge publishes a list of 

 fresh-water algae from North America preserved in the Museum at 

 Stockholm. The new species described are Glosterium psmdolunula 

 and Anabsena californica. 



Action of Mineral Waters on Diatoms. %— A. Lauby has investigated 

 the causes of the presence of brackish- water species of diatoms in some 

 of the strata of Mount Dore and the neighbourhood. The deposits are 

 of Tertiary origin, and the author, for reasons here set forth, believes that 

 the brackish-water and marine species argue the presence in the old 

 Tertiary lakes of mineral springs, somewhat similar to that of Saint- 

 Nectaire at the present day. Species of diatoms, showing the same 

 variation, were found in the mineral waters of Saint-Nectare and in the 

 old deposits of Courancon. The development of certain peculiarities is 

 explained. 



Green Coloration of Oysters.§ — L. Calvert and P. Paul give an 

 account of their experiments with the " Diatomee bleue " (Navimda 

 ostrearia Bory) in connection with oyster culture in the south of France. 

 The green oysters of Marennes are much esteemed by gourmets, con- 

 sequently attempts were made to induce the oysters in the great tanks 

 or basins at Balaruc-les-Bains (Herault) to assume the green coloration 

 naturally, the coloration being due to the presence of the aforesaid 

 diatom. Genuine green oysters of Marennes were introduced into the 



* Tuft's College Studies, ii.No. 3 (1909) pp. 77-480 (18 pis.), 

 t Arkivf. Botanik. viii. (1909) No. 13, pp. 1-29 (1 pi.). 

 t Comptes Rendus, cxlix. (1909) pp. 529-32. 

 § C.R. Soc. Biol. Paris, lxvi. (1909) pp. 1036-8. 



