408 SUMMARY OF CUKKENT EESEAECHES KELATING TO 



Structure of Spermatozoids of Fucacese.*— H. Kylin has made 

 a study of the spermatozoids of Fucus serratus, and has cleared up 

 various uncertainties as to their structure, and the parts played by the 

 nucleus and cytoplasm respectively. He finds in the young antheridium 

 a relatively large nucleus with a nucleolus, a frothy cytoplasm (Wabeu- 

 struktur), greenish-yellow chromatophores adjacent to the nucleus, and 

 certain small strongly refractive bodies containing fucosan and fat. 

 The nucleus by repeated division gives rise to sixty-four daughter- 

 nuclei, the antherozoids ; gradually as division takes place the colour of 

 the chromatophores disappears and their place is taken by leucoplasts. 

 The colour reappears in the sixty-four-nuclear stage, changing from 

 greenish-yellow to orange. These intensely coloured orange chromato- 

 phores constitute the eye-spot of the antherozoid. The free antherozoid 

 is pyriform, 4-5 /^ long, 2 • 3-2 • 5 /-c broad ; the flagella are unequal, the 

 posterior one being twice as long as the anterior. He notes that the 

 first division is one of reduction, giving thirty-two haploid chromosomes. 

 The author failed to find the " ISTebenkernorgane " of Retzins. The 

 chromatophore of the antherozoid is lacking in fucoxanthin, and 

 contains carotin or xanthophyll, or both these pigments. 



Sarg-assum.t — F. S. Collins gives a resume of the principal papers 

 relating to the Sargasso Sea, and discusses the species of Sargassum and 

 other algfe found floating there. The predominant species is S. natans 

 (L.) J. Meyen, which through long pelagic existence has become so 

 differentiated from its original ancestor (attached to rocks) that this 

 latter cannot now be identified. The plant exhibits active vegetative 

 growth, but propagates only by fragmentation, and it has a much 

 specialized fauna associated with it. It occurs in scattered patches 

 through an area in the North Atlantic bounded by the Gulf Stream and 

 its subsidiaries, reaching the coast of Europe, thence south and again 

 west to the Gulf of Mexico : fragments may be driven by high winds to 

 the shores of New England and Northern Europe. It" is accompanied 

 by S. flultaiis Borgesen, but in less quantity, and less differentiated from 

 its presumed ancestor, the shore-growing S. Hystrix J. Ag. Of equal 

 distribution, but in relatively minute proportion, is A scophi/Uimi nodosum 

 (L.) Le Jolis — which is practically undifferentiated from the parent 

 plant ; but though floating and fruiting freely for weeks, probably for 

 months, it cannot be considered persistent in the pelagic condition. 

 Finally, there is a sterile Cystoseira, resembling C. crinita Bory, found 

 once only ; its status therefore is uncertain. 



Spanish Algae.J — B. Lilzaro e Ibiza in his Spanish Flora gives 

 descriptions of the genera and species of fresh-water and marine algae, 

 illustrated with a number of text-figures. He includes 494 species. In 

 the scarcity of other literature on Spanish Algfe the present work 

 deserves to be kept in mind. 



* Ber. Deutsch. Bot. Gesell., xxxiv- (1916) pp. 195-201 (2 pis.). See alsoNuov. 

 Notarisia, xxviii. (1917) p. 137. 



t Bhodora, xix. (1917) pp. 77-84. 



X Compendio de la Flora Espauola. Madrid: Hernando (1906) i. ed. 2, 

 pp. 178-280 (figs.). 



