786 SUMMARY OF CURRENT RESEARCHES RELATING TO 



central group in the stolons ; (2) the difference in structure of the 

 bundles in the stem and in the stolons ; (3) the absence of roots on the 

 mother- stem, if the stolons are regarded as of a cauline nature ; (4) the 

 structure is always similar in the roots and in the stems of Ferns ; (5) 

 the roots of second and third order are monostelous, like the stolons. 



Algae. 



Phyllactidium, Phycopeltis, and Hansgirgia.*— Dr. G. B. Toni 



assigns reasons for regarding Phyllactidium arundinaceum Mont, as 

 a species of FTiycopeltis, which must now be known as Phycopeltis arun- 

 dinacea. He does not agree with Hansgirg in identifying Hansgirgia 

 flahelUgera with Phycopeltis. He affirms an important difference between 

 the two genera, Phycopeltis being reproduced by non-sexual zoospores, 

 Hansgirgia by sexual zoogametes, like Trentepohlia. Mycoidea he regards 

 as occupying an intermediate position between the Coleochsetacese and 

 the (Edogoniacese. 



Conjugation of Spirogyra.f — Mr. C. B. Atwell describes a case of 

 conjugation in Spirogyra longata, in which, in two instances, the contents 

 of a male cell have passed into two female cells, forming a zygosperm 

 in each. 



Volvox minor. I — Prof. J. A. Eyder discusses the fore and aft poles, 

 the axial differentiation, and a possible anterior sensory apparatus in 

 V. minor. In every colony there was an empty pole, which was always 

 anterior ; the direction of the rotation of the colonies is not constant, 

 and may be either sinistral or dextral; but the direction of progress 

 always coincides with an imaginary axis passing through the centre 

 of the anterior empty pole and the posterior germ-bearing portion 

 of the nearly spherical colony. The diameter of a colony is slightly 

 longer along the axis round which it revolves than in the direction 

 transverse to it, so that the form of the whole is that of a very slightly 

 oblong spheroid. The " eye-spots " found in the flagellate cells of the 

 anterior pole of the colony were the largest, and as one passes in suc- 

 cession backwards the spots are seen to gradually diminish in size, until 

 at last they are barely distinguishable. This arrangement revives the 

 question as to whether these eye-spots are not really sensory organs. 

 Prof. Eyder remarks that he has been unable to find any notice of any 

 of the features of Volvox here described, and he expresses a hope that 

 some microscopist will take up the study of Volvox anew, and publish a 

 well-executed drawing of it. 



Fungi. 



Blastomyces. § — MM. J. Costantin and EoUand describe a new genus 

 of Mucedineas to which they have given the name Blastomyces. The 

 followdng is the diagnosis : — A filamentous fungus forming at its ex- 

 tremity short branches which give rise both to the primary and secondary 

 spores. Each fructifying branch is thus transformed into a pulverulent 

 sporiferous mass. Aquatic and aerial chlamydospores on the mycele. 



* Bot. Centralbl., xxxix. (1889) pp. 182-4. Cf. this Journal, ante, p. 419. 



t Bot. Gazette, xiv. (1889) p. 154 (1 fig.). 



X Ann. and Mag. Nat. Hist., iv. (1889) pp. 253-4. 



§ Rev. Mycol., xi. (1889) p. 166. 



