ZOOLOGY AND BOTANY, AIIGROSCOPY, ETC. 475 



it is very thin and shows nnmerons gland-cells ; in the thickened zone 

 there are, besides gland-cells, more nnmerons epithelial cells and some 

 muscle-fibres. The cbffita3 are implanted in this region, which secretes 

 a periostracnm. The chaitte are carefully described, as also the peduncle, 

 the median tentacle, the discoidal lophophore, the four pairs of cirri, 

 the pigment-spot or " eye," the statocyst. An account is given of the 

 alimentary system (spherical algje and a few diatoms were present in the 

 gut) and coelomoducts or nephridia. 



Phylactolsematous Polyzoa from Volga Region.* — Nelson Annan- 

 dale reports on a collection mostly from the Jeruslan river, a tributary 

 of the Volga. All the species are true Paltearctic forms, and only 

 one of them {Flumaiella punctata) has as yet been found within the 

 limits of the Oriental region. The Phylactolrematous fauna of the 

 Volga is probaljly transitionary between that of Europe and that of 

 Central and Xorth-eastern Asia. The author discusses Fredicella sultana, 

 sub sp. jordanim, and the genus Plumatella and its species. 



Rotatoria. 



Sex and Food Conditions in Rotifers.f — D. D. Whitney has added 

 to his previous work on Hydatina senta an experimental study of other 

 five rotifers with regard to the control of sex by food. In pedigreed 

 cultures of Hydatina senta a diet of the colourless flagellate Polytoma, 

 w^hich is probably a poor diet, causes female-producing daughters to be 

 produced, whereas a diet of the green flagellate, ChJamydomonas 

 pulvisculus, which is probably an optimum food, causes nearly all 

 male-producing daughters to appear. In mass cultures of Brachionus 

 pala a scanty diet of miscellaneous green flagellates caused nearly all 

 female-producing females to be produced, whereas a superabundance of 

 this same green diet caused in some experiments 95 p.c. of male- 

 producing daughters to appear. In all cases the results were similar ; a 

 scanty diet produced mainly females, but when the rotifers were 

 transferred to a culture-water containing abundant food the percentage 

 of males rose very high. 



Echinoderma. 



Influence of Hypertonic Sea-water on Echinoid Ova. J — Arthur 

 Russell Moore finds that the eggs of Arljada punctuJata treated with 

 acidulated sea-water show a rhythmicity in sensitiveness to a hypertonic 

 solution. Normally fertilized eggs also show a rhythmical susceptiliility 

 to hypertonic sea-water. 



The hypertonic treatment may have one of two opposite effects upon 



« 



* Trans. B. Soc. Edinburgh, ii. (1915) pp. 73-82. 

 t Journ. Exper. ZooL, xx. (1916) pp. 263-95. 

 X Biol. BuUetin, xxviii. (1915), pp. 253-9. 



