ZOOLOaY AND BOTANY, MICROSCOPY, ETC. 495 



The sexual generation includes a vegetative structure composed 

 of whorls, primary and secondary fascicles, cortical filaments, and 

 secondary prothallium ; but the author founds the primary divisions 

 of the genus on the character of the trichogyne, according as it is 

 pedicellate or sessile ; in the latter case it may be ovoid or in the 

 form of a club or truncated cone. In the process of impregnation, 

 the author maintains the actual absorption of the wall of the tri- 

 chogyne at the point of contact of the poUinidium, the passage of 

 protoplasm from the latter through the orifice thus formed, and the 

 appearance of a septum at the base of the trichogyne which separates 

 the cystocarpic vesicle. The rejuvenescence of the protoplasm at the 

 close of impregnation imparts a great activity to this cell, which then 

 begins to bud and to produce the fertile glomerulus from which 

 proceed the carpospores or oospores. 



M. Sirodot describes thirty-three native and exotic species of 

 Batracliospermum, which he classifies under six sections, viz. : — 

 Batrachosperma Setacea, Moniliformia, Helminthoidea, Turficola, 

 Hybrida, and Yiridia. 



Stephanospliaera pluvialis.* — Prof. G. Hieronymus has made 

 some further observations on this organism, especially with reference 

 to the conjugation of the microzoospores. 



While confirming in the main Cohn and Wichura's observations, 

 the author attributes to the enveloping membrane a high degree of 

 elasticity. It is perforated by two orifices for the two cilia of each 

 primordial cell. These vegetative primordial cells or macrogonidia 

 always possess a red eye-spot, which had not been previously observed. 

 When about to divide, which is usually in the afternoon, these pri- 

 mordial cells retract all their protoplasmic threads by which they 

 were attached to the enveloping membrane, round themselves off, and 

 then divide into microgonidia. Usually all the cells of a vegetative 

 family become transformed into microgonidia at the same time, though 

 there are exceptions to this rule. 



The microgonidia, microzoospores, or gametes unite in the ordi- 

 nary way by conjugation, their anterior ends coalescing in the 

 production of zygotes, zygospores, or isosj)ores, which are scarcely 

 larger than the original microgonidia. Those which did not con- 

 jugate were found in all cases to perish ; the resting-cells are always 

 the result of the conjugation of microgonidia. Germination of the 

 resting-spores was not observed. 



Classification of the Lower Algse.f— D-- A. Hansgirg proposes a 

 fresh classification of the unicellular fresh- water Algae, insisting at 

 the same time upon the point that the terms species, genus, &c., must 

 not be understood in the same sense as with the higher plants, it 

 being necessary in the lowest orders of vegetable life to describe and 

 distinguish many forms which are but stages of development of others 

 classified in quite a different group. 



* Cohn's Beitr. Biol. Pflanzen, iv. (1SS4) pp. 51-78 (2 pis.). 



t Oester. Bot. Zeitschr., xxxiv. (18S4) pp. 313-8, 351-8, 3S9-94 (1 pi.). 



