328 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Timmia elegans Hagen.* — C. Meylau describes the microscopical 

 characters of Timmia eJegatis Hagen, which is synonymous with T. comata. 

 It is a Scandinavian plant ; but Meylan has found it on the Jura 

 mountains also. 



Frullania Rappii.t— A. W. Evans gives an account of FruUania 

 Rappii, a new species collected in Florida by S. Rapp. He describes in 

 detail the morphology and structure of the plant, and indicates its 

 affinity to F. cobrensis, a Cuban species. 



Thallopliyta. 

 Algae. 



(By Mrs. E. S. Gepp.) 



Nannoplankton and the Centrifugal Method. | — H. Lohmann 

 discusses nannoplankton and the enormous advantage of separating it 

 out by centrifugalization. Besides macro-, meso-, and micro-plankton, 

 two new terms are now in use, megalo- and nanno-plankton. The last 

 named consists of the very smallest organisms, down to 1 /x in diameter, 

 and abounds more in fresh water than in the sea, comprising Gymno- 

 dineffi, Chrysomonadineas, and bacteria. The most effective apparatus 

 for catching nannoplankton is that of such plankton-animals as 

 Appendicular ia, OikopUura, etc. ; such an apparatus may contain 1000 

 to 40,000 Protista, exclusive of bacteria. Centrifugalization is infinitely 

 superior to filters and sedimentation for extracting nannoplankton from 

 water, the proportions for the three methods being respectively 150 to 9. 

 The author uses a machine giving 1400 revolutions per minute, and 

 keeps it going for 7 minutes. By using this method Gran has found 

 that the Sargasso Sea, hitherto reported to be poor in plankton, is in 

 reality very rich in forms of nannoplankton too small to be captured 

 with silk nets. 



Vernal Phytoplankton.§ — W. A. Herdman writes on the vernal 

 phy to plankton maximum — that is, a complex made up of the maxima of 

 several different species or groups of species which seem to occur in a 

 definite sequence, varying with the year. Individual species or groups 

 of species may be more abundant in one year than in another. Thus 

 in 1911 Biddulphia reached its maximum in March, Chsetoceras in May, 

 Rhizosohiiia in June. The abundance of the latter, in a calm sea and 

 in sunshine at Port Erin, gave a characteristic iridescent glistening 

 appearance to the water. 



Dinoflagellate and Diatoms on Beach. || — W. A. Herdman de- 

 scribes a discoloration of the beach at Port Erin in April 1911, which 

 was due to some diatoms and an abundant Peridinian, Amphidinium 

 opercidatum. In June the discoloration consisted of a Navicida without 

 a trace of Amphidinium. 



* Rev. Bryolog., xxxix. (1912) pp. 19-20. 

 t Bryologist, xv. (1912) pp. 22-6 (figs.). 



+ Internat. Rev. gesammt. Hydrobiol. u. Hydrogr., iv. (1911) pp. 1-3S (5 pis. 

 and figs.). 



§ Nature, Ixxxvi. (1911) p. 517. || Nature, Ixxxvi. (1911) p. 554. 



