﻿Notes 071 Fossils from Prince Charles Foreland. 161 



himself, has a much more robust zoarium (as much as f of 

 an inch in diameter), composed of fewer zosecia, the bent 

 portion of which is much longer than that in the present 

 species. The Stenopora crassa of subsequent authors pos- 

 sesses a zoarium composed of superimposed colonies, a 

 character which is absent in S. cidariformis. 



Stenopora, sp. indet. 

 (Plate VIII. Figs. 9 and 10.) 



The collection contains a few fragments of a Stenopora 

 characterised by an irregularly- shaped zoarium, which is 

 partly cylindrical and partly frond escent. No complete 

 specimen having been obtained, a definite description of the 

 external characters of this Stenopora is impossible; neither 

 is it possible to estimate the ultimate size of the entire 

 zoarium. Of the fragments observed, the cylindrical portion 

 attains 12 mm. in diameter, a size which must have been 

 greater in the frondescent one. 



Microscopical Fxamination, — In both portions of the 

 zoarium the mature region of the zosecia is at right angles 

 to the axial one ; but through lack of suitable longitudinal 

 sections, the wall-structure could not be satisfactorily studied, 

 yet it appears to be distinctly moniliform. On the other 

 hand, an important character has been observed, viz., 

 diaphragms are present in the outer part of the immature 

 region, and probably also in the mature one ; they are very 

 scarce, and quite straight, with a large central perforation. 



Tangential sections show rather numerous immature zosecia, 

 and two sets of acanthopores ; those at the junction angles 

 are very large, with a well-defined structure ; the smaller 

 ones are as in the previous species. 



The different form of growth, and the presence of 

 diaphragms, differentiate this species from the two others 

 described in this note; but not enough is known of its 

 characters to enable one to establish the nature of its 

 affinities when comparing it with the other members of the 

 genus Stenopora. 



VOL. XVII. 



