56 Prof. J. W. Gregory — Fossil Corals from Egypt, etc. 



The tetrameral arrangement reminds me of SfijJina favjasi, 

 Ed. & H./ but in that species the primary and secondary septa are 

 equal. 



LEPTASTE^A, Edwards & Hairae, 1848. 

 Lkptastr^a barkoni, n.sp. (PI. VI, Fig. 8.) 



Diagnosis. — Corallnm large and massive, with subplane upper 

 surface ; and the corallum is built up of long, narrow, cylindrical 

 corallites ; but on weathered edges, and in sections, it appears to be 

 made of successive layers. 



Corallites long and cylindrical; narrow; 2-3 mm. in diam., and 

 often oval in section. On fresh surfaces the edges of the corallites 

 are slightly raised. The walls, seen in section, are thin and 

 connected by fine, vesicular exotheca. The corallites are close 

 together, being separated by a very narrow band of exotheca, which, 

 is marked on the surface as a narrow groove around the calicular 

 edges ; but occasional calices are so crowded that the calicular 

 edges are in contact. 



Septa thin ; they are long in the primary cycle ; those of the 

 secondary cycle may reach half-way to the axis, but in the interior 

 they may reach the enlarged trabecular columella. The third cycle 

 is little more than rudimentary. Primary septa exsert. 



Columella appears as a small tubercle from the surface, but 

 sections show that it is trabecular. It is of medium size, and then 

 joins the two first cycles of septa. 



Dimensloiis. — Corallum : — 



Leug-th 185inm. 



"Width 15o ,, 



Tliickness 75 ,, 



Corallites : — 



Diameter 2-3 ,, 



Calicinal centre : — 



Arerage distance 3-3'5 ,, 



Disirihtdion. — Miocene : top of the Abu Sha'ar Plateau, west of 

 the Bed Sea, south-west of Jebel Zeit, II 18G4. 



Figures. — PI. VI, Fig. 8a, part of surface, by 2 diam. ; Fig. 86, 

 another part of the same specimen, by 2 diam. ; Fig. 8c, section of 

 interior of the same specimen, by 2 diam. 



Affi,nities. — This coral is well preserved and its features are very 

 distinct. The narrow diameter of its corallites gives it a close 

 resemblance to Plesiastrcea, but it has no pali. The coral which 

 seems to be its nearest all}' is tlie recent Red Sea coi"al, Leptastrcsa 

 hottai (Ed. & H.),- which has a less conspicuous, less substyliform 

 columella. L. hottai, moreover, may have a fourth cycle of septa, 

 and its primary and secondary septa are described by Klunzinger as 

 equal ; and its corallites are from 3 to 4 mm. in diameter. 



1 Edwards & Haime: Hist. nat. Cor., vol. ii, p. 243. 



- Edwards & Haime : Hist. nat. Cor., vol. li, p. 486, pi. d7, tig. 1. Klunzinger : 

 op. cit., pt. 3, p. 44, pi. V, fig. 9. 



