ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 371 



Incertae Sedis. 



Bryozoa of Georgian Bay.* — H. T. White reports on seven species 

 and one variety of Phmiatella, from the Georgian Bay region. He 

 divides Plumatella polymorpha Kraepelin into V. repens, P.fungosa and 

 P. appressa. The well-known Pectinatella magnified and Cristatella 

 mucedo are also reported. 



Australella and Allied Polyzoa.t — Xelson Annandale discusses the 

 genus Australella which he established in 1910 and referred to the 

 Lophopime. He now recognizes it as one of the Plumatellinae and 

 defines it as follows : — Pluuiatellinre in which the colonies are recum- 

 bent and dendritic, hut enclosed in a uniform apparently structureless 

 jelly that fills up the interstices between individual zocecia and branches. 

 There is no stolon ; the zocecia arise directly one from another. 

 Individually they are semi-recumbent, the proximal part of each resting, 

 when the branch to which it belongs is fully formed, on the object to 

 which the colony is fixed, while the distal part is almost vertical. The 

 polypide is normal ; it has some forty to sixty tentacles, which are mod- 

 erately or very long. The lophophore generally resembles that of Pluma- 

 tella. The statoblasts are large (0"4-l mm. long), but as a rule smaller 

 than those of the Lophopinse. They resemble the free statoblasts of 

 Plumatella in structure, and have neither marginal processes nor 

 terminal prolongations. The genus is represented in Australia, India, 

 and South America. Three species are dealt with, as also a new variety 

 of Plumatella punetata and two species of Stolella. 



Rotatoria. 



Sex-determination in Hydatina senta.} — David D. Whitney finds 

 that in the parthenogenetic reproduction of this Rotifer the influence of 

 the diet acting upon the grandmother determines the sex of the grand- 

 children. A continuous diet of the colourless Flagellate, Potytoma, 

 causes female grandchildren to be produced. A sudden change of the 

 diet from Polytoma to an abundant supply of the active green Dunaliella, 

 another Flagellate, causes male grandchildren to be produced. The 

 regulation of the sex-ratio in the parthenogenetic reproduction of 

 Hydatina senta can thus be controlled by the food conditions. 



Inheritance of Hydatina senta. § — A. Franklin Shull obtained two 

 parthenogenetic lines of this Rotifer from England and from Nebraska. 

 Tiny were found to differ in important respects. The eggs of the 

 Nebraska line were larger than those of the English line. Measurements 

 to demonstrate this difference were made only upon eggs laid in the 

 first twenty -four hours of egg-laying of any female, because ii was found 



* Suppl. 47th Rep. Dept. Fisheries, -Ottawa, 1915, fasc ii. pp. 195-9. 

 t Records Indian Museum, xi. (1915) pp. 163-9 (2 pis.). 

 X Journ. Exper. Zool., xvii. (1914) pp. 545-58. 

 § Journ. Exper. Zool., xviii. (1915) pp. 145-86. 



