ZOOLOGY AND 150TANY, MICROSCOPY, ETC. 013 



season and rate of growth, more especially of microscopic species, have 

 been observed and the results are given. 



The enemies of lichens also are treated by the authors, including 

 insect and parasitic fungi, with well-marked' instances of protective 

 resemblance in moths, etc. 



Origin and Development of the Apothecium in Collema pul- 

 posum.* — F. M. Bachmann publishes a further paper on the reproductive 

 sti'uctures in this hchen, dealing more especially with the cytology of the 

 subject. She gives a resume of similar previous work on lichens, with 

 the results arrived at by the various workers. She describes the forma- 

 tion of a pore or opening in the cross-walls of the multiseptate trichogyne 

 to allow the passage of the male nucleus ; and she also describes the 

 nuclear content of the spermatia and of the ascogonia and ascogenous 

 hyph^e. Following fertilization the ascogone cells increase in size, no 

 new septa are formed, and the original septa are resorbed, so that the 

 ascogonium becomes practically one cell. The nuclei increase by division. 

 The ascogenous cells rising from the ascogonium show consideral)le 

 variation in size and also in their content. They may contain one or 

 several nuclei, and only little cytoplasm. There is, she states, no posi- 

 tive evidence of a fusion of nuclei in the ascogonium of Collema jmljjositm, 

 though the position of the nuclei sometimes strongly suggests that a 

 fusion is occurring or about to occur. 



Bachmann has also followed nuclear division in the ascus, and has 

 evidence of a second reduction probably in the second division of the 

 nuclei in the ascus : and the evidence is strongly in favour of two 

 previous nuclear fusions : a sexual fusion in the ascogonium and a second 

 fusion in the ascus. The author thinks that the cases of apogamy in 

 lichens may prove to be similar to Collema pulposiwi, with spermatia 

 developed internally and trichogynes that never reach the open. She 

 considers it proved that the spermatia of lichens are male gametes and 

 not asexual conidia. 



Schizopliyta. 

 Scliizoinycetes. 



Gaertner Group Bacilli in Rats.f — W. G. Savage and W. Y. Read 

 describe their investigations on rats for the presence of organisms 

 belonging to this group. The purpose of the enquiry was to ascertain 

 whether such types are found normally in healthy rats. The internal 

 organs and intestinal contents of forty-one rats were examined, and in 

 five cases bacilli identical with B. enter itidis were found (in the spleen 

 in each case). The sera of several rats agglutinated the organism in 

 high dilution. These facts point to an old infection with Gaertner 

 group bacilh, possibly associated with the laying down of Danysz virus. 

 The general conclusion is that while rats are susceptible to infections of 

 this type, these bacilli are not natural inhabitants of their intestines. If 



* Arch. ZeUforsch., x, 4 (1913) pp. 369-430 (7 pis.), 

 t Journ. of Hygiene, xiii. (1913) pp. 343-52. 



