CORALS FROM THE UPPER GREENSAND. 59 



Tribe ASTREINtE (p. xxxi). 



Genus Parastrea (p. xliii). 

 Parastrea stricta. Tab. X, fig. 3, 3 a. 



Corallum composite, forming a mass not very tall, and slightly convex on its upper 

 surface. Calices seldom circular, in general oblong or irregularly polygonal, projecting 

 very little, and having always distinct margins. Costa delicate, closely set, nearly equal, 

 almost horizontal, nearly straight or slightly bent, and united by their extremity to those of 

 the neighbouring corallites, which, however, remain circumscribed by a small furrow. 

 Calicular fossula shallow. Columella of a dense tissue, subpapillose, and not much developed. 

 Septa thin, broad, closely set, terminated by a series of calicular dentations, the last of 

 which (towards the columella) appears to be more developed than the others ; the number 

 of these septa seldom exceeds forty, and they are rather unequal. Walls thin, but well 

 developed. Diameter of the calices, usually between two lines and two lines and a half ; 

 distance between the calices, at least half a line. 



This species, found in the Greensand at Blackdown, is characterised from a specimen 

 belonging to the Geological Society ; it differs from all the previously described Parastrea 

 by the approximation and delicate structure of the septa. 



Mr. Morris mentions, in his ' Catalogue of British Fossils,' 1 two other species which 

 have been found by M. Austen in the Greensand at Haldon, and which belong to the family 

 of Astreidae. M. Austen considers the one as being identical with the Maestricht 

 fossil coral described by Goldfuss under the name of Astrea elegans? and he refers 

 the other to the Astrea esc/iaroides 5 of the same author 4 . We regret not having had 

 an opportunity of examining these fossils. 



1 Loc. cit., p. 31. 



2 Petref. Germ., vol. i, tab. xxiii, fig. 6. 



3 Goldfuss, op. cit., tab. xxiii, fig. 2 ; fossil from Maestricbt. 



* Austen, on the Geol. of the South-east of Devonshire, Trans, of the Geol. Soc, Second Series, vol. vi, 

 p. 452. 



