346 Dr. L. Radlkofer on Fecundation in the Vegetable Kingdom, 



closed spermatozoids, as Monads ; the former observed the sper- 

 matic vesicles with the spermatozoids imperfectly extricated 

 from them^ and described them as actively-moving, stalked 

 molecules, possessing a tail. Later observers, as Mirbel*, over- 

 looked this motion. Ungerf first distinctly observed the sper- 

 matozoa themselves, and called them Spirillum hryozoon. De- 

 caisne and Thuretf observed their cilia. Hofmeister§, who, 

 following Nageli ||, traced the antheridia back to the first cell, 

 could find only two cilia in Pellia. Schacht^ did not see more 

 than one anywhere. 



The statements of Gottsche** and Schachtftj that the an- 

 theridia of some Liverworts have the envelope composed of a 

 double layer of cells, — and those of linger J J, Schleiden§§, and 

 Schacht II II, that the whole of the spermatic vesicles are contained 

 in one large cell whose wall lies immediately beneath the enve- 

 lope, — are in contradiction to the observations of Hofmeister^^. 



The archegonia, for a knowledge of whose whole course of 

 development we are likewise indebted to Hofmeister, in their 

 earliest stages exactly resemble the rudimentary antheridia. 

 When fully developed, they consist of flask-shaped organs, 

 mostly stationed at the ends of the shoots, and surrounded by 

 special leaves [perichaetium, Mosses), or cup-like envelopes [calyx, 

 Liverworts) ; more rarely they are immersed in the flat stem 

 [Riccia). The axial row of cells of each archegonium loses its 

 horizontal walls by solution, so that they are converted into a 

 canal, which leads below into an enlarged cell (central cell of 

 the archegonium) lying in the expanded part, and at the epoch 

 of puberty opens at the top by the separation of the uppermost 

 layer of cells bounding it. According to Hofmeister***, the 

 central cell of the archegonium contains a daughter-cell formed 



* Compl. des Obs. sur Marchantia. Mem. de I'lnstit. de France, xiii. 

 p. 377. Paris, 1835. 



t Ueb. Anthere v. Sphagnum. Flora, 1834, i. p. 145. — Neuer Beob. lib. 

 die Moos-authere, &c. Nova Acta A. C. L. C. xviii. pt. 2. p. G87. — Weitere 

 Beob. ub. die Samenthiercb. derPflanzen. Ibid. p. 785 (Ann, des Sc. nat. 

 2 ser. xi. p. 257, 1839). 



X Ann. des Sc. nat. 3 ser. iii. p. 14 (1845); xvi. pi. 10-14 (1851). 



§ Vergleich. Untersuch. &c. Leipsic, 1851, p. 16. 



II Zeitscbr. f. wiss. Botanik, Heft i. p. 172. Zurich, 1844. 



IT Das IMikroskop, &c., 2nd ed. Berbn, 1855, p. 86. 



** Nova Acta, xx. pt. 1. p. 2fM. pi. 16, fig. 8, 



tt Pflanzenzelle, p. 109; Mikroskop, p, 83, 



XX Nova Acta, xviii, pt, 2. p, 689, pi, 53, fig. 1, b. 



§§ Grundz. d, wiss. Botanik, 3rd ed. ii. pp. 67 & 80, 



nil Pflanzenzelle, p, 110, 



nil Vergleich, Unters. &c. Leips, 1851, pp. 43, 69 ; and Flora, 1855, 

 p. 438. 



*** Flora, 1854, p. 269. 



