AND GLYPHASTRiEA, DUNCAN (1887). 227 



Fig. 11. Another portion of the inner layer, showing small holes in the 

 spaces between the ridges. Enlarged forty diameters. 



12. A portion of the exterior, lateral surface of the wall or theca of a 



eorallite of S. Forbesi, showing transverse growth-lines crossing 

 the pseudo-costal spaces, and the longitudinal furrows along the 

 lines of the septa. Enlarged twenty diameters. 



13. Part of a ti-ansverse section of the upper portion of a eorallite of 



S. Forbesi, showing the disposition of successive layers of stereo- 

 plasm, with which the interlocular spaces are completely filled. 

 Enlarged twenty diameters. From the type specimen in the 

 British Museum, 



14. A longitudinal section of the upper portion of a eorallite of 



S. Forbesi, showing the limitation of the deposit of stereoplasm to 

 the space immediately above the uppermost horizontal dissepi- 

 ments, and the arched lines of deposition of this material within 

 the eorallite. Enlarged seven diameters. 



15. A single interlocular space in a eorallite of S. Forbesi, viewed from 



beneath, showing the development of the horizontal dissepiment 

 frona the bounding walls of the septa, and the sutural lines at the 

 meeting of the membrane. Enlarged fifteen diameters. 



16. A transversely fractured eorallite of S. sexradiata, viewed from 



beneath, showing the complete enclosure of the individual inter- 

 locular spaces by the septal laminee. Enlarged sixteen diameters. 



17. A calice of 8. Forbesi, showing impressed longitudinal grooves in 



the inner surface of the wall, between the principal septa, for the 

 insertion of the mesenterial muscles. Enlarged six diameters. 



Discussion. 



The President remarked upon the complicated question of nomen- 

 clature which was raised in the case brought before the Society by 

 the Author. The latter part of his paper added valuable informa- 

 tion on the structure of corals, and was a striking instance of the 

 aid that might be afforded by palaeontological research to the studies 

 of biologists. 



Mr. Alfred Foord said the drawings in Prof. Duncan's memoir 

 had been carefully made from the original specimens, and that the 

 existence of a columella in Glyj>hastrcea was distinctly visible, as 

 shown in several of the figures. 



Mr. Etheridge was well acquainted with the specimens, and 

 called attention to the great difficulty there was in correctly deter- 

 mining their species from the appearances presented. The research 

 relative to the present species was almost unprecedented. Dr. Hinde 

 had taken great pains in unravelling the history of these corals, and 

 his investigation of their microscopic structure was of great im- 

 portance, and would probably lead to valuable results in the future 

 classification of the Coelenterata. 



Dr. Woodward agreed with Dr. Hinde as to the distinctive cha- 

 racters of 8. Forhesi and S. sexradiata, and complimented him 

 on the clearness of his description. 



Dr. Hinde, in reply, said he had not questioned the general accu- 

 racy of Mr. Foord's drawings ; but in two instances, in the plate 

 referred to, the figures were admittedly diagrammatic, and the 

 crucial feature in another figure had been exaggerated, no doubt 

 unintentionally on the artist's part. The speaker considered the 

 use of the microscope essential for the correct determination of coral 

 structure. 



