STRUCTURE OF SERIATOPORA, POCILLOPORA, ETC. 3!)1 



Notes on the Structure o/' Sertatopora, Pocillopora, Coral- 

 LiUM, and TuBiPORA. By Professor H. N. Moseley, 

 P.RS. 



Beriatopora and Pocillopora, 



When Professor Louis Agassiz had discovered that Millepora 

 was a Hydroid, and not an Anthozoau, he concluded from the 

 fact that Pocillopora and Seriatopora were provided like it with 

 tabulae, that these genera also were to be assigned to the 

 Hydroida. Quoy and Gaimard had, however, figured the twelve 

 tentacles of Pocillopora; Verrill examined the coral in 1872, 

 and showed that it was clearly Madreporarian ; and I subse- 

 quently also examined its structure myself. Although from the 

 close resemblance of the corallum of Seriatopora to that of Pocil- 

 lopora it seemed almost certain that the former was also Madre- 

 porarian, the fact has never hitherto been proved, nothing as yet, 

 as far as I know, having been published concerning the structure 

 of the soft tissues of this genus. I have, therefore, been on the 

 watch for specimens of Seriatopora preserved in spirits, and have 

 just found an excellent specimen of S. suhidata amongst a most 

 valuable series of objects collected at Zanzibar by Mr. G. Gulliver, 

 jun., M.A., M.B. The coral proves to exhibit peculiar structures of 

 very great interest. It is clearly Madreporarian. The polyps, which 

 are oval in outline, bear twelve short tentacles with rounded 

 knobs disposed in two series. When these tentacles are retracted 

 they are covered over by the indrawn margins of the disc, as in 

 Actinia. There are twelve mesenteries only, of unequal depths, 

 two of which bear very long mesenterial filaments, whilst the 

 others appear totally devoid of filaments. The inter-mesenterial 

 chambers are closed by the body-wall beneath, forming a series 

 of pouches, which fit into the conical depressions in the inter- 

 septal spaces of the calicles of the corallum. They are of various 

 lengths, to suit the varying depths of these depressions. Two 

 of them are enormously long, and in the decalcified lamina of 

 soft tissue removed from the corallum are seen, when this is 

 viewed from beneath, projecting from the under surface of each 

 polyp hke a pair of long conical horns. These are the prolon- 

 gations of the walls of those inter-mesenterial chambers which 



