24 Coelenterata. 



Flitter records observations on the metabolism of anemones, which indicate 

 that Actinia equina gives off incompletely broken down products (which de- 

 colourise permanganate), and also takes up from the sea-water soluble organic 

 compounds (which decolourise permanganate). He also discusses the symbiosis 

 of Aiptasia diaphana with zoochlorellas. 



Wietrzykowski( J ) describes the egg-cleavage of Edwardsia beautempsi. About 

 2 y 2 hours after fertilisation the egg begins to segment, and 4 equal and clearly 

 separated blastomeres are at once formed. 20 minutes later the cleavage- 

 furrows begin to disappear, so that the embryo becomes perfectly spherical. 

 But about 20 minutes later the blastomeres reappear; there are now 8 of them. 

 This phenomenon appears to be quite normal. Eggs placed in a very dilute 

 solution of toluidine blue showed, at the time when the outlines of the 4 blasto- 

 meres disappeared, on the surface of the embryo, two cross-lines corresponding 

 in position to the primitive cleavage-furrows. This indicates that there is not 

 a fusion, but only a resserrement of the 4 blastomeres previous to the next 

 cleavage. The subsequent cleavages proceed normally, except that sometimes 

 at the 8-cell stage the blastomeres appear to fuse in pairs (i. e., producing 

 4 blastomeres), and then, 20 minutes later, cleavage into 16 cells takes place. 

 The cleavage results in the formation of a blastula without obvious polarity. 

 The endoderm is formed by unipolar budding. The larva is ciliated all over 

 and swims actively. It elongates, and develops at its anterior end a girdle 

 of stronger cilia. An ectodermic invagination at the posterior end opens into 

 the archenteron. Finally the endoderm is raised into 8 folds, the mesenteries. 

 Such larvae lived in aquaria for a month without changing their form or deve- 

 loping tentacles. 



Cary( 1 ) collected Zoanthina and Zoanthella (Hensen's and Semper's larvae) 

 in abundance at the border of the Gulf Stream, south of the Tortugas, and 

 placed them in aquaria. Only the specimens of Zoanthina underwent trans- 

 formation. The circular band of large cilia was resorbed, the larva} became 

 inactive and settled to the bottom, each becoming attached by the aboral end, 

 and developing 8 tentacles. The young actinians did not advance beyond this 

 stage, although kept for some weeks. 



Gravier( 3 ) describes colonies of Galaxea, from the bay of Tadjourah, in which 

 a large part of the surface was perforated by small Sabellids, which traversed 

 the coenenchyme through and through. In some cases the colonies were ab- 

 solutely ravaged by perforating organisms. Around the necrosed areas there 

 had taken place a proliferation, which resulted in the production of a large 

 number of new calicles, bringing about more or less considerable deformation 

 of the surface of the colony. The most abundant parasites of G. are Cirripedes 

 (Pyrgoma), which almost always fix themselves in the calicles. Calicles, on 

 the summits of which P. are living, frequently show no traces of septa, there- 

 fore the P. became fixed to the calicles during the early phases of the latter, 

 and arrested or prevented the development of the polyps. Nevertheless the 

 walls of such calicles were raised to the same level as those of neighbouring 

 calicles. Debris of shells etc., which had fallen on to the colony, had been cover- 

 ed by a layer of living substance by the neighbouring polyps, and from this 

 living layer new polyps had been produced by budding. One colony showed an 

 area in which were numerous dead polyps and a single living one. The latter 

 had given rise by budding to a series of new ones. All the living polyps 

 round the margin of the dead area had proliferated abundantly on the face 

 turned towards the dead part. 



Gravier( 4 ) describes the coral-reefs, chiefly coral-patches, of the bay of Tad- 



