ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 199 



no arcbegonia. The author suggests that the rarity of this widely- 

 distributed species is due to its having been overlooked, owing to its 

 great resemblance to Lenina, with which it grows. E. S. (r. 



Mean Annual Thermal Life-Conditions of Webera nutans and 

 of Leptoscyphus Taylori in the Elbe-sandstone Mountains. — A. 

 ScHADE (Ber. Deutsch. Bot. Ges., 1917, 35, 490-505; see also Bot 

 Gentralhl., 191S, 138, 153). An account of the temperatures recorded 

 by means of thermometers plunged in living tufts of the Bryophytes 

 under observation, controlled by synchronous observations of the 

 temperatures of the air and of the substrata upon which the plants 

 grew. In a sunny place the Webera tufts attained a temperature 20° C. 

 and more above that of the air, whereas the Leptoscyphus growing in 

 the shade had a temperature 8 ' 5° C. below that of the air. The highest 

 temperature recorded for a moss was-56*8° C, and that was in a Webera 

 tuft which had previously reached a minimum of - 9*7"C. This 

 species can therefore tolerate such a range of temperature as 66*5° C. ; 

 whereas the range recorded for the hepatic did not exceed 23' C. The 

 mean temperature for the year was, for the Webera 23'3°C., and for 

 the Leptoscyphus 6'2''C. The two plants grew but 50 metres apart, 

 and indicate two climates of marked contrast within a very narrow 

 area. A. G. 



Thallophyta, 

 Algae. 



New Species of Peridiniese. with Remarks on the Structure of 

 the Outer Membrane in Gymnbdinium and Glenodiniura. — J. 

 WoLOSZYNSKA {Bull. Acad. Sci. Gracovie, 1917, 57, Ser. B., 114-122, 

 3 pis.). All genera of Peridiniete, including OymnocUnium, possess a 

 more or less delicate outer membrane, which in the simplest forms is 

 composed of small hexagonal plates. In more highly developed forms 

 the arrangement of the plates is more complicated, reaching its highest 

 point of development in Feridimum, Geratlum and Gonyaidax. The 

 following points are characteristic of the simple structure of the outer 

 membrane : the minute size, the large and inconstant number of the 

 plates, and their regular hexagonal form. The alteration in the 

 arrangement of the plates generally begins first in the longitudinal 

 furrow, then spreads to the hypovalve, later to the epivalve, and iinally 

 to the transverse furrow. The number of the plates decreases markedly 

 in the higher genera, and remains constant. The structure of the 

 outer, membrane must always be taken into account in systematic keys. 

 The author gives a short diagnosis of the characters of the outer 

 membrane of all species of Gymnodinium and Glenodmium which she has 

 examined. Several new species and varieties are described, found near 

 Lemberg, Sphserodinium Umneticum Wol. 1917 is identical with 

 Glenodmium cinctum Ehrenb. E. S. G. 



Asterocystis de Wildeman and Asterocystis Gobi.-^A. Pascher 

 {Beih. Bot. Gentralbl., 1917, 35, 578-79). Asterocystis Gobi 1879 

 is an alga ; while Asterocystis de Wildeman 1893 is an oomycete, for 

 which the author suggests the name Olpiidiaster . Asterocystis radicis de 

 Wildeman therefore = 0. radicis Pascher. E. S. G. 



