ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 677 



Extrusion of Gametes in Fucus.* — Ceorge J. Peirce gives the 

 result of bis experiments in connection with the fruiting tips of Fucus 

 evanescens Ag. He shows that the gametes effect their escape from the 

 conceptacles while still under water ; and the contraction of the external 

 ct lis of the thallns, as a result of being left half dry at low tide, is not 

 necessary to the ejection of the sexual organs, though such contraction 

 may hasten the process. The extrusion of the gametes is effected by 

 mechanical pressure which is developed within the plant, and the con- 

 traction and compression as a result of drying merely supplement this 

 pressure. 



The Genus Trentepohlia.| — F. Brand treats of the structure of 

 T rentepoldia under various headings and compares his own results with 

 those of previous writers. The sections of his paper are entitled Cell- 

 wall, Cellulose caps, Cross-walls and Pore-formation, Growth and 

 Branching, Sporangia, Physiological and biological conditions, Poly- 

 morphism, Method of preparation and staining, and New forms. Under 

 " Cell- wall " the author refers to the characteristic roughnesses on the 

 outer wall of mature cells and to the lamellate structure of the walls. 

 In the main he is able to confirm the statement of Correns concerning 

 the formation in T. iolithus of funnel-shaped lamellae. He finds the 

 same thing in his new species T. Negeri. 



The development of the cellulose caps has been traced by the author 

 from an early stage, and they are shown to be the remains of dead 

 terminal sporangia or of end cells. The manner of their formation is 

 described. 



The cross-walls of Trentepohlia are said to arise without preliminary 

 thickening or folding, and it is impossible to detect any division of the 

 cross-wall into layers such as is commonly seen in Cladophora — the 

 septum is simple. As regards the pores in the cross-walls, the author 

 quotes the results of Karsten and others, and gives his own experience 

 on dried material ; he hopes that comparative examination on living 

 plants may lead to interesting results with regard to delimitation of 

 species. The growth of Trentepohlia is unlimited, although it may 

 apjjear to be terminated by the formation of sporangia, for after the 

 shedding of the spores the basal cell of the sporangium grows up 

 through the empty sporangium to form new vegetative shoots or repro- 

 ductive cells. The method of branching is fully dealt with. 



The sporangia may arise from the base of the plant or on the fila- 

 ments, and in the latter case they may be either terminal, intercalary 

 or grow from the side of the filament. The form of the sporangium 

 may also vary, being either round, bottle-shaped, or hooped ; and the 

 author describes here a new shape which he has found on a new species, 

 T. annul at a. This he describes as having funnel-shaped sporangia, 

 which when ripe are obliquely oval and are distinguished from the 

 round sporangia by having two short, funnel-shaped rings of cellulose 

 close to each other, between the sporangium and the stalk-cell. The 

 author was unable to study the development of these rings as fully as 

 he could have wished owing to lack of fresh material. 



The section containing the author's views from a biological staud- 



* Torreya, ii. (1902) pp. 134-7. 



t Beih. z. iiot. Centralbl., xii. (1902) pp. 200-25 (1 pi.) 



