564 SUMMARY OF CURRENT RESEARCHES RELATING TO 



different forms have been known as : B. Ottomiilleri with var. rotundata, 

 Jl. anthropomorpha, covered with spines or horns projecting more or less ; 

 B. punctata, with vars. subtriundiduta and subaurita, covered with 

 punctuations ; B. translucida with neither spines nor punctuations. 

 B. polymorpha is rare or absent in surface collections, and is principally 

 found at a depth of 20-120 m. and between latitudes 65-70°. The 

 various forms this species may assume are described and figured. The 

 author does not consider that season is the cause of the-polymorphism. 

 Another instance given is Eucampia antarctica, which includes as its 

 forms E. balaustium and Molleria antarctica. These are discussed and 

 figures of various forms are given. Other species which show poly- 

 morphism are : Rhizosolenia polydactyla, Biddulphia striata, and certain . 

 species of Chsetoceros. The author maintains that the structure of the 

 endochrome is a more fixed character than the form and variety of the 

 sculpture of the valves, since it remains constant throughout a species, 

 notwithstanding variety of outward form. And he complains that 

 diatomists do not easily shake off the old method of diatom nomenclature, 

 founded on the form and structure of the shell. Petit's lines of study, 

 founded on characters of the endochrome, have not been followed except 

 for plankton diatom. 



Microspora amoena.* — K. Meyer describes the development and life- 

 history of Microspora ammna Rab., and compares it with M. Willeana, 

 which was studied by Lagerheim. The differences in the chromato- 

 phores of the two species, and indeed in their life-history, are so marked, 

 that the author considers each to represent a distinct group, possibly a 

 distinct genus. Thus Microspora Thur. and Microspora (Thur.) Lager- 

 heim are not in the least synonymous. The nuclei, formation of zoo- 

 spores, and the akinetes of M. amoena are described in detail. 



Oogenesis in Hormosira.f — M. R. Getman writes on the oogenesis 

 in Hormosira. He first describes its morphology and then briefly sum- 

 marizes the oogenesis of Fucacere in general. A short account is given 

 of what happens in Hormosira, in which genus eight nuclei are formed 

 and eight eggs begin to develop. The final 4- nucleate condition is 

 reached by the breaking down of four immature eggs, rather than of 

 four free nuclei. Such a condition is safely interpreted as less - removed 

 from the Fucus condition than forms in which the 4-nucleate stage is 

 reached by the breaking down of free nuclei. The author shows a series 

 of oogenesis in Fucaceee, beginning with eight eggs in Fucus and ending 

 with a parthenogenetically developed egg in Sargassum. 



Marine Algae of the Danish West Indies.! — F. Borgesen publishes 

 an account of the Phsaophycea) of the Danish West Indies. This forms 

 the second part of his monograph of the marine algae of that region. In 

 the Phaeosporales he treats of the Ectocarpacese and seven more families. 

 In Encoeliacese he places a new genus, Rosenvingia, which is allied to 



* Ber. Deutsch. Bot. GeselL, xxxi. (1913) pp. 441-8 (1 pi.). 

 t Bot. Gaz., lviii. (1914) pp. 264-71 (1 pi. and figs.). 

 % Dansk. Bot. Arkiv, ii. (1914) pp. 157-224 (44 figs.). 



