12 



Scientific Proceedings, Royal Dublin Society. 



(" Thanmantias "), in June, 1885, at Kingstown, county Dublin. 

 I have observed several phases of its development, but could not 

 obtain a sufficiently complete series to definitely state of what 

 Actinian it is the larval form. My opinion, however, is, that 

 it will prove to be the young of H. chrysanthellum. 



The above communication is but a further contribution to the 

 systematic knowledge of our British Actiniae. I am fully aware of 

 the morphological iuterest connected with the free Actiniae, and 

 though I have made some anatomical investigations on this form, 

 I refrain from publishing them till I have examined a sufficient 

 number of other sea-anemones to render a description and com- 

 parison profitable. 



Fig. 1. — Side view of a fully extended Halcampa chrysanthellum, magni- 

 fied about 2 diameters. 



,, 2. — Generalized diagram of markings of oral disc and tentacles. 



,, 3. — Side view of capitulum and tentacles. 



,, 4. — Transverse section through the lower portion of the capitulum. 

 The following points should be noted : — The arrangement 

 of the muscular bands on the twelve mesenteries ; the ex- 

 istence of a pair of very small secondary mesenteries in 

 the alternate intermesenterial chambers ; the existence of 

 a pair of deep sagittal oesophageal grooves, which are pro- 

 vided with long cilia, and of five obscure furrows on each 

 side of the ciliated oesophagus. 



[Figs. 2, 3, and 4 are placed in the same relative position, and are not 

 drawn to scale.] 



