302 QUARTERLY CHRONICLE OF MICROSCOPICAL SCIENCE. 



structure, and produced sporangia from which zoospores 

 were discharged. He has also met with cases in wfiich 

 Collema produced young individuals of Nostoc by a kind of 

 pullulation. 



IV. Hepaticae. — Kienitz-GerlofF has published (' Bot. 

 Zeit,,' March'and April, 1874) the result of his studies in the 

 development of the sporogonium of Riccia, Marchantia, 

 Preissia, Pellia, Metzgeria, Frullania, Radula, Liochl(sna, 

 Lepidozia, Jungermannia, and Cahjpogeia. 



V. Marattiaceae. — 1. Angiopteris. — Tchistiakoff has re- 

 published (' Ann. des Sc. Nat./ 5e ser., xix, p. 219) an 

 elaborate memoir originally printed in Russian on the 

 development of the sporangia and spores of Angiopteris. 

 The purport of the research is rather to throw light on the 

 general theory of the vegetable cell. The detailed obser- 

 vations differ in some respects from those of Luerssen and 

 Russow. The theoretical considerations are in harmony with 

 those of Brucke and Hanstein in regarding the protoplasm 

 as an organism inferior to an amoeba because deprived of its 

 individualisation. The nucleus and nucleolus are regarded 

 as structures brought about by the equilibrium of forces to 

 which the protoplasm is exposed, and are therefore by no 

 means characteristic of it in its most active condition. 



2. Scolecopteris. — E. Strasburger describes in the ' Jen- 

 aische Zeitschrift ^ (1874, pp. 81-95) the structure (especially 

 of the sporangia) of Scolecopteris elegans, Zenk., a species 

 of Marattiaceee from the Permian of Chemnitz. The details 

 were perfectly preserved in chalcedony, which allowed admi- 

 rable sections to be studied. In an additional plate he 

 figures the structure of the sori of Angiopteris evecta, and 

 Marat tia Kaulfussii. 



VI. Lycopodiaceae. — Aster oph/llites. — Prof. Williamson 

 has described the histology of this very remarkable extinct 

 type in an elaborate memoir (' Phil. Trans./ 1874, pp. 41 — 

 81) with illustrative plates. 



The Oldham form in its youngest state first appears as a 

 mere twig, having a central vascular axis enclosed in a 

 cortex. The vascular axis consists of reticulated vessels ; 

 its transverse section is triangular. The cortex consists of 

 an outer prosenchymatous (sclerenchyma?) and an inner 

 parenchymatous layer. As the plant grew successive vas- 

 cular layers appear to have been added to the exterior of the 

 vascular axis. In the Burntisland type the features were 

 essentially the same, but the vessels were barred and not 

 reticulate. The fructification already described by the 

 author as Volkmanma Dawsoni is now regarded by him as 



