ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 387 



intermediate between fixed cilia and vibratile cilia. The space in which 

 the cilia are formed, on the surface of the chaetoblast, corresponds to an 

 intra-cytoplasmic vacuole. 



Nematohelminthes. 



Minute Structure of Cells in Ascaris megaiocephala.* — B. Romeis 

 has studied the plastosomes and other details of structure in the muscle- 

 cells and in the cells of the uterus and the intestine. He deals in the 

 present communication chiefly with the epithelial lining of the uterus. 

 The cells are connected at their bases by narrow bands, but the Ijodies of 

 the cells protrude into the lumen like separate villi. The villus-like por- 

 tion often bears a clul)-like process, which has an amoeboid character. 

 As regards activity, a secreting and an absorbing function must be re- 

 cognized. The cells secrete the viscid fluid which is found between the 

 eggs and a digestive ferment w^hich acts on degenerating sperms. The 

 sperm-debris is absorbed. 



The cytoplasm is full of plastosomes, which are arranged in a long 

 thread in a well-defined reticulum. There is also a supporting fibrillar 

 framework in the cytoplasm. There are also fat-globules and vacuoles, 

 besides other complications. 



Platy helminthe s . 



British Fresh-water Turbellaria.t — Henry Whitehead makes a 

 welcome addition to our knowledge of British fresh-water Turbellaria. 

 He deals with the Rhabdocoelida, giving a general account of them, and 

 communicating notes on typical species collected in the neighbourhood 

 of London — Catenula lemnee, Microstomum linear e, Dalyellia viricUs, 

 species of Mesostoma, Bothrotnesostoma personamm, and Gyratrix herma- 

 'pliroditus. A list is given of the thirty species which have been recorded 

 from the British Isles. 



Incertae Sedis. 



Variations in Hooks of Statoblasts in Pectinatella mag'nifica.l 

 Annie P. Henchman and C. B. Davenport have studied the margin 

 hooks. The number varies from eleven to twenty-six, and inside one 

 and the same colony there is great variability. There is a marked 

 difference in the average number of hooks in mid- and late-summer 

 statoblasts, and the study suggests that this is not merely due to the 

 differences of age, temperature, and food conditions in the two seasons, 

 but probably also to the circumstance that the biotype that forms many 

 hooks is one that develops later in the season than the others. 



EcMnodernia. '~ .^ 



Eyes of Starfish. § — Helmuth Plessner has studied the function of 

 the eyes in Asteria^ ruhens and Solaster papposus^ and finds that they 

 perceive distant illumination which is in contrast positively or negatively 



* Anat. Anzeig., xliv. (1913) pp. 1-14 (1 pi.). 



t Journ. Quekett Micr. Club, xii. (1913) pp. 45-56 (1 pi.). 



X Amer. Naturalist, xlvii. (1913) pp. 361-71. 



§ Zool. Jahrb., xxxiii. (1913) pp. 361-86 (7 figs.). 



