272 ME. J. E. DUEEDElf ON 



surface view eight longitudinal darker and lighter areas were- 

 clearly marked, the coloured areas corresponding with the 

 mesenterial chambers, and the colourless with the line of origin 

 of the mesenteries. The mouth was already indicated at the 

 broader end as a slightly depressed, small, circular aperture ; 

 the aboral end was narrow and rounded (PI. 18. fig. 4). 



The perioral ectoderm differed from the remainder of the 

 outer layer in being dark brown in colour, owing to the inclusion 

 of zooxanthellse. Some of these apparently worked their way 

 out from the ectodermal cells and adhered superficially, or, in 

 other cases, became free. Their presence at various heights 

 in this restricted region is also revealed in sections. 



Contrary to the usual condition in the Actiniaria, the ciliation 

 was imiform over the whole surface. The larvse progressed with 

 the narrower, aboral end foremost, and also attached themselves 

 finally by this extremity. Even during the first day their power 

 of adherence to the bottom and sides of the vessel was considerable, 

 sufficient to resist a strong current of water from a pipette. 



The description given applies to each^ of the larvse extruded, 

 all having apparently reached a similar stage of development. 

 The subsequent growth, so far as followed, was likewise the same 

 in each. No earlier stage could be seen through the transparent 

 tissues of the adult, and when a polyp was cut in halves none 

 floated out. It is evident, then, that in Lebrunia, as appears to 

 be also the rule in many other Zoantharia, the ova are ripened 

 and the embryos develop and are expelled in batches ; for, were 

 it otherwise, difi'erent stages would be represented within the 

 gastro-coelomic cavity at one and the same time. 



Such, however, is not always the case. While at Port Antonio, 

 on the north-east coast of Jamaica, working in the temporary 

 Marine Laboratory established there in 1897, by the Johns 

 Hopkins University, specimens of Aulactinia stelloides, McMur., 

 were collected, and from these larvae were also being set free. Here 

 the individuals, each with an aboral tuft of longer, less mobile 

 cilia, were thrown out from the internal cavity of the adult by 

 the same jerking motion as in Lehrunia ; but many different 

 stages were represented in one parturition, and a like variety of 

 phases could be observed through the partly transparent tissues. 

 Minute planulge, showing what seemed to be the beginning of 

 an invagination, would appear along with larvse possessed of eight. 



