432 SUMMARY OF CUKRENT RESEARCHES RELATING TO 



Habits of Sea Anemones.* — H. J. Fleure and C. L. Walton, from 

 a study of Actinia, Tealia, and Anthea, conclude that the base and the 

 tentacles are more sensitive than the other parts to mechanical stimuli. 

 In Anthea and Actinia the tentacles are insensitive to chemical stimuli, 

 unless these are excessive, and the mouth is the region specially sensitive 

 to chemical stimuli. Motor stimuli can be communicated from the 

 tentacle to the mouth, and vice versa. Pieces of filter-paper placed on 

 some of the tentacles of an Actinia were carried to the mouth, but after 

 a few trials, lasting over 2-b days, were rejected by these tentacles. 

 Actinia showed no reaction to light, and Tealia a variable one. Sagartia 

 bellis expanded at nightfall. Eolis papillosa is the anemone's most 

 formidable enemy. They are attacked also by Trochus zizyphinus and 

 by crabs. 



Mesoderm of Coelentera.t — C. Dawydoff describes in the larva of 

 the Xarcomedusan SohnundeUa mediterranea a distinct mesodermal 

 layer. He considers that this embryo closely resembles the embryo of a 

 Ctenophore or of an Annelid, and that the facts favour a near relation- 

 ship of Cnidaria and Ctenophora. The mesoderm of SohnundeUa, in 

 part at any rate, arises from the ectoderm. 



Hydroids of Bermuda. J — E. D. Congdon gives an account of 

 eighteen species, eight of which are new, viz., Euclemlriimi lairgitti, 

 Chjtia fragiUs, C. simplex, Halecium bermudense, H. marki, Sertularella 

 speciosa, S. humilis, and Thyrocyphus intermedins. This is the first list 

 for Bermuda. Few hydroids are found on the exposed southern shore. 

 In a few places especially favourable to hydroid life on the opposite 

 shore, the straggle for foothold is so marked that seven of, the small 

 species may be found growing on the larger forms. The Bermuda 

 hydroids show a close relationship to those of the West Indies and the 

 Gulf of Mexico. 



Seasonal Variation in Hydra orientalis.§ — N. Annandale describes 

 how H. orieatalis migrates into deeply-shaded corners during the hot 

 weather. It is then small and colourless, has only 4 tentacles, and 

 bears one or two 4-tentacled buds. About the beginning of Novemljer 

 the deeply-pigmented, 6-tentacled winter form appears. This cycle 

 seems to be the result of degeneration caused by the unfavourable 

 climate. 



Irene ceylonensis.||- — N. Annandale notes the occurrence of this 

 Medusoid, recently described by Browne, from Ceylon, in a brackish 

 pool in the Ganges delta. He also describes the hydroid stage. It is 

 very minute, with a branching hydrorhiza, bearing at intervals single 

 hydrothecae, and gonothecffi containing a single Medusoid. 



Notes on Ctenophora.^ — Fanny Moser discusses some Ctenophora col- 

 lected by Pictet and Bedot at Amboina (Sunda Islands), e.g. Hormifpliora 



* Zool. Anzeig., xxxi. (1907) pp. 212-20. 

 t Tom. cit., pp. 119-24 (6 figs.). 



X Proc. Amer. Acad., xlii. (1907) pp. 46.3-85 (.37 figs.). 

 § Journ. and Proc. Asiatic Soc. Bengal, n.s., iii. (1907) pp. 27-8. 

 II Tom. cit., pp. 79-81 (1 fig.). 

 \ Zool. Anzeig., xxxi. (1907) pp. 786-90 (1 fig.). 



