406 SUMMARY OF CURKENT RESEARCHES RELATING TO 



Bahama Islands, including a new species, Hymenostomum Jlavescens, a 

 description and figures of which are given. A. G. 



Hyophila subcucullata.— R. S. Williams {Bryologist, 1921, 24, 

 22, 2:3, 1 pi.). A description of a new moss species from the San Diego 

 river, Cuba ; it is allied to H. microcarpa. A. (1. 



Thallophyta. 



Alga3. 



Investig-atioiis Concerning the Plant and Animal Life of the 

 High Seas. — H. Lohmann {Veroff. Inst. 3Ieeresk. Univ. Berlin Geogr. 

 not. Reilie., 1912, 1, 90 pp., 2 pis., 14 text-figs. ; see also Bot. Centralbi, 

 1918, 138, 185). A report on the biological work carried out during 

 the voyage of the " Deutschland " from Bremerliaven to Buenos Ayres, 

 May to September, 1911. The average density of organisms for the 

 entire area traversed was for the following depths : — U m. 95U0, 50 m. 

 5700, 100 m. 1500, 200 m 500, 400 m. 350 individuals per unit. The 

 superficial area is therefore not poorer than the 50 m. stratum, as was 

 also shown later by Schiller. The suiface of the cooler regions has a popu- 

 lation nine times greater than that of the tropics. The depths from 

 50-400 m. is at the most twice as thickly populated. The average 

 number of organisms was five times less in the tropics than in the 

 cooler waters, the protophytes predominating. Northern waters were 

 seven times richer than the tropics, and nearly twice as rich as the 

 south. The naked phytofiagellates attained their maximum (2600 

 individuals) on the surface, as well as all the other protophytes except 

 the Diatoms, Chroococcaceai, Coccolithophorids, SilicoflagellatEe, and 

 PeridinicEe (including Gymnodinieae). A new genus and four new species 

 are described in Coccolithophorida;. Tropical water is poor in net- and 

 centrifugal-plankton. E. S. Gepp. 



Simple Method of Studying the Nannoplankton of Fresh Water. 

 — E. Naumann {Naturiv. Wochensclir., N. F., 1916, 15, 180-3, fig. ; 

 see also Bot. Centralbh, 1918, 138, 375). The author proposes to 

 make careful examinations of the intestines of fresh-water animals, 

 both as a means of obtaining easily nannoplankton, and of adding to 

 our knowledge of the nutrition of zoopkmkton. Tlie nannoplankton 

 obtained by him in the intestines of Bosiuia and Diapluinosoma would 

 pass through the smallest mesh of any net. Organisms possessing a 

 shell, such as Diatoms, are sufficiently well preserved as to be mounted 

 in Canada balsam, and the gelatinous and other algte {Trachelontonas 

 volvocina, etc.) in glycerine. Both methods supplement each other. 

 He found that Cydotetla is a main constituent of the food of Entomos- 

 tracge in the lakes of Southern Sweden, and he here records their occur- 

 rence for the first time in those waters. Larger Entomostracte of the 

 plankton feed largely on Diatoms. E. S. G. 



Note on a " Blood " Lake. — H. Leber {Internat. Rev. ges. 

 Hydrohiol. Hydrogr., 1915-10, 7, 131-3 ; see also Bot. Centrcilbl., 



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