402 SUMMARY OF CURRENT RESEARCHES RELATING TO 



He considers that Sticliococcus may one day have to be sunk into Hor- 

 midium or Ulothrix. The author agrees with Kiitzing in regarding 

 Hormidium as a section of Ulothrix, consisting of aerial forms, which 

 possess a discoid chlorophore lying against the cell wall. He describes 

 fully the two types, Ulothrix flaccida Kiitz. and U, cre?itilata Kiitz. 



Synopsis of Scenedesmus.* — J. Brunnthaler pubhshes a systematic 

 synopsis of the genus Scenedesmus (ChlorophyceEe), containing twenty 

 species with varieties, distribution, and principal synonymy ; also an 

 analytical key based on the structural characters of the species, varieties, 

 and forms. 



Notes on Diatoms. f — W. M. Bale publishes notes on certain of the 

 discoid diatoms, in which he surveys some of the principal characters 

 which have been used to discriminate the species. The genera he treats 

 of are Ooscinodiscus, Actinocyclus, Aster omphahis, and Actinoptychus. 

 He criticizes and discusses the views and treatment of other authors, 

 and states his opinion as to the value or otherwise of the characters em- 

 ployed by them ; suggesting others from his own experience. 



Observations on Diatoms. if — J. Pavillard publishes a series of 

 critical notes on the structure of sundry pelagic diatoms of the Western 

 Mediterranean — CJisetoceros decipiens Cleve, 0. Lorenzianum Grunow, 

 C. tortilisetus Mangin, G. GlandaziMsingm, 0. costatum smd G.pseudohreve 

 (both new species), Bacteriastrum delicatulum Cleve var. princeps, 

 Rldzosolenia setigera Brightwell, R. semispina Hensen, R. calcar-avis 

 Schultze, Hemiaulus chinensis Grev., II. Hauckii Grunow. Some of 

 these species are figured. 



Remarkable Species of Gomphonema.§ — Weinhold publishes a 

 description of a remarkable new diatom, a species of Gomphonema, 

 which he regards as a transitional form between Gomphonemacese and 

 Achnanthacege. The curving of the frustules in the girdle view and 

 the unequal number of stride on the two valves, point to Achnanthace^ ; 

 but the cuneate shape of the valves, the median nodule and raphe 

 which are present on both sides afford full proof, he thinks, that the 

 plant belongs to the Gomphonemacese and, indeed, to the Asymmetricse. 

 He therefore names it Gomphonema dispar, and considers that it settles 

 the systematic position of the genus Rhoicosphenia. 



Rhizoids of Spirogyra.|| — E. M. Delf describes and figures rhizoids 

 which she has found on Spirogyra adnata (?), growing on a log in a 

 pond at Hampstead. The rhizoids may be either lateral or terminal. 

 It seems probable that the rhizoids are formed primarily as the result 

 of contact stimulus. 



* Hedwigia, liii. (1913) pp. 164-72 (27 figs.). 



t Journ. Quekett Micr. Club, xii. (1913) pp. 17-44. 



J Bull. Soc. Bot. France, Iviii. (1911) pp. 21-9 (figs.). 



§ Hedwigia, liii. (1913) pp. 134-7 (fig.). 



II Ann. of Bot., xxvii. (1913) pp. 366-8 (figs.). 



