646 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Btatemenl of Campbell, who denies the presence of ;i sterile cell between 

 the two antheridia and the root-cell, was not confirmed, in agreement 

 with the investigation of Belajeff. BelajcfT was not clear aboui the 

 time of the appearance of the root-cell. It has been determined by the 

 present study that the root-cell is formed as a result of the second 

 division of the germinating microspore. 8. The spermatozoid is a 

 spirally coiled body having numerous cilia at the anterior end, aud a 

 large vesicle at the posterior end. 9. A blepharoplast, which first 

 appears in the cytoplasm, and later elongates towards the nucleus, was 

 observed in each sperm-cell. 10. Three to fiye archegonia are usually 

 formed in each female prothallium, and each archegonium consists of 

 one egg-cell, a ventral canal-cell, a neck canal-cell with two nuclei, and 

 the neck-cells. 11. Only one spermatozoid enters into the egg-cell. After 

 the penetration of the spermatozoid into the egg-nucleus there appears 

 in the cavity of the latter a nucleolus-like body, derived very likely from 

 the spermatozoid, and somewhat smaller than the nucleolus. 12. The 

 four quadrants are clearly distinguishable in the young embryo. The 

 development of the root-quadrant ceases at an early stage, and later its 

 tissue cannot be distinguished from that of the foot. 



Spore-distribution in Selaginella.* — F. W. Neger discusses the 

 question of spore-distribution in Selaginella helvetica and S. spinulosa, its 

 meaning, mechanism, etc. He confirms all that Ooebel had discovered 

 as to the macrospores being liberated spontaneously by the dehiscence of 

 the sporangial wall, and as to their dissemination preceding that of the 

 microspores ; also as to the more rapid germination of the microspores. 

 Neger finds, however, that in some cases the microsporangia of the apex 

 of the spike open first, then follow the macrosporangia below, and finally 

 the microsporangia at the base. Thus there are always microspores 

 ready to germinate when the macrospores are ready for them ; and cross- 

 fertilization is favoured. He notices in the dorsiventral fertile spikes 

 of S. helvetica that the macrosporangia are principally on the ventral 

 side and the microsporangia on the dorsal. He attributes this to the 

 better nutrition of the ventral side. 



Lyginodendron (Crossotheca) in Irish Coal Measures.f — T. John- 

 son gives a resume of the literature on Lyginodendron. oldhamium, 

 Rachiopteris aspera, Sphenopteris Hdninghansi, and Kaloxglon Hookeri, all 

 vegetative parts of one fossil type, the reproductive organs of which are 

 represented by Crossotheca Hdninghausi, Lagenostoma Lomaxi, and 

 Calymmatotheca. Johnson found specimens in the Dublin Museum 

 which add confirmatory evidence, and he describes and figures them. 

 His conclusions are as follows : 1. The Pteridosperineas flourished in 

 Ireland. 2. The Museum specimens confirm the view that Sphenopteris 

 Hdninghausi is really the foliage of the Pteridosperm Lyginodendron old- 

 hamium Will. {Crossotheca Honinghausi Kidst.). 3. Calymmatotheca 

 Stangeri Stur. occurs in continuity with Sphenopteris Honinghausi, and 

 is simply the de-seminated fertile frond of this type. 4. In the Grlen- 

 goole Coal Measures, Co. Tipperary, a seed impression attached to the 



* Flora, ciii. (1911) pp. 74-7 (1 fig.). 



+ Sci. Proc. Roy. Dublin Soc, xiii. (1911) pp. 1-11 (2 pis.). 



