640 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the existing species Haliseris delicatula and Stenogramma interrupts . 

 The paper includes also remarks on the fossil genus Haliserites, with 

 special reference to H. Dechenianus Gopp. 



From the Upper Silurian of Indiana the same author * describes and 

 figures two new species of Buthotrephis, B. divaricata (= B. speciosa) 

 and B. Neivlini. The name speciosa is suggested later as a substitute 

 for divaricata, the latter having been already used for another alga, 

 B. divaricata Kidston. Notes on the genus Buthotrephis are given, and 

 a likeness is pointed out between this genus and Liagora. 



Origin of the Sporophyte.f — B. M. Davis discusses this question 

 from the point of view of the structural changes that occur in the cell- 

 protoplasm at the time of fertilisation, such change being made visible 

 at least in the alteration of the number of chromosomes in the nuclei. 

 A gametophyte contains in each of its nuclei a fixed number of chromo- 

 somes proper to the plant ; its fertilised egg has twice that number of 

 chromosomes as the result of the fusion of two nuclei ; the resulting 

 sporophyte is also characterised by this double number of chromosomes 

 until it produces asexual spores — in which the chromosomes revert to the 

 original ancestral number as found in the gametophyte. In the higher 

 animals the life-history is strikingly different ; for here the gametes 

 have half the normal number of chromosomes. Among plants the 

 explanation must be sought amongst the lowest orders — the Thallophytes. 

 But unfortunately we know almost nothing of what occurs in the Algas 

 and Fungi ; and what we do know is confusing. Until their life- 

 histories are properly understood we can only proceed by speculation. 

 The author discusses the peculiar limited conditions that occur in Fucks 

 and Chora ; and then passes on to the cases of the Rhodophyceas and 

 Ascomycetes, which afford pronounced evidence of a Sporophyte genera- 

 tion. Similar tendencies are afforded also by (Edogonkim, Splmroplea, 

 Ulothrix, and the Conjugales ; these also he discusses. The points 

 emphasised are that the sporophyte is a phase intercalated after the 

 fusion of the gametes — the protoplasm resulting from this fusion being 

 structurally different from that of the gametophyte. It is wound up, as 

 it were, to a higher pitch of vitality ; and it tends to express itself in 

 morphological developments, dependent on the environment. Finally, 

 it reverts to the ancestral type of protoplasmic structure by producing 

 asexual spores which lead back to the gametophyte phase. 



Fungi. 



Notes on Monoblepharis.l — Roland Thaxter summarises the species 

 of this genus, five in number. He dissents from Lagerheim's view that 

 the genus should be split, two species being placed in Diblepharis, and 

 considers that they form a well-defined and coherent group. Thaxter 

 promises a thorough examination of the New England forms. 



Leptomitus lacteus.§ — R. Kolkwitz publishes preliminary notes 

 on his research of this fungus. He found that it grew well on slices 



* Proc. U.S. Nat. Mus., xxix. pp. 261-70 (3 pis.) ; and Proc. Biol. Soc. Washington, 

 xv. (19(t2) p. 86. See also Nuov. Notar., xiv. (1903) pp. 132, 144, 145. 

 t Amer. Natural., xxxvii. (1903) pp. 411-29. 

 J Rhodora, v. (1903) pp. 103-8 (6 rigs.). 

 § Ber. Bot. Ges., xxi. (1903) pp. 147-50. 



