72 SUMMAKi^ OF CURRENT RESEARCHES RELATING TO 



proliferation and the gastric partitions, appear simultaneously. There 

 are not any septal funnels. Each cord differentiates into columellar 

 mass and stalk muscle. The author describes the development of the 

 sub-umbrella, the sub-umbrella saccules, the partitions of the basigaster 

 (distinct from those of the gastro- vascular cavity), the endodermic 

 epithelium, and the gonads which arise at the expense of the pigmented 

 epithelium. 



Limnocodium sowerbyi.* — The late Robert Douglas re-described 

 the external features of this fresh-water medusoid, which occurred in 

 1905 in the Victoria regia pond in the Munich Botanical Garden. 

 Attention may be called to his observation that the club-like otocyst, 

 which has no concretions, arises from a group of endoderm cells. Only 

 males were found. The position of Limnocodium is beside Afflaurojisis 

 agassizii in the family Petasidae. The distinctive features are : one 

 kind of tentacles, no attaching organs, no centripetal canals, four radial 

 canals, egg-shaped gonads, and club-shaped otocyst. 



Porifera. 



Merlia and Monticulipora.t — R. Kirkpatrick finds that Media 

 normani Kirkp., a siliceous sponge with a supplementary calcareous 

 skeleton, owes its exceptional character to being infested with a Zoo- 

 xanthella, which passes a resting stage in certain cells of the sponge and 

 a mobile phase outside these cells. The calcareous skeleton is formed 

 around the corpses of the monads. Merlia is a lineal descendant of the 

 Palasozoic Monticuliporas, all of which are siliceous sponges with supple- 

 mentary skeletons formed of the calcified bodies of monads which had 

 lived commensally in the cells of those sponges. The Monticuliporas 

 proper, also species of CJiseteies and Rhaphidopora, all contain siliceous 

 spicules of a kind related to those of Merlia, and, further, the calcareous 

 skeleton is formed on the same plan. 



Protozoa. 



Peristomial Cilia. J — Georg Weber has made a study of the move- 

 ments of the cilia around the mouth of Blepharisma lateritium, Stentor 

 cmrideus, and Spirostomum teres. There is flexion and straightening of 

 the cilium almost in one plane, but associated with a slight twisting on 

 the cilium's own axis. The details of this combination of flexion and 

 twisting are discussed, and the beating of the cilium is brought under 

 the general law of pendulum movement. 



Irritability of Infusorians.§ — Th. Yieweger distinguishes tropho- 

 taxis or anataxis to nutritive substances, aero taxis, hydrotaxis, al- 

 kaliotaxis and oxytaxis (sensitiveness to alkalis and acids). He finds 

 that Paramcecium is sensitive to chemical changes in the medium, to 



* Zeitschr. wiss. Zool., cii. (1912) pp. 92-110 (1 pi. and 2 figs.). 

 t Proc. K Soc, Series B, Ixxxv. (1912) No. B582, pp. 562-3. 

 X SB. k. Akad. wiss. Wien, cxxi. (1912) pp. 3-48 (1 pi. and 15 figs.). 

 § Arch. Biol,, xxvii. (1912) pp. 723-99 (1 pL). 



