﻿part 4] PHILLIPS ASTHMA HENNAHJ, AND OBIONASTUJEA. 



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but the extrathecal tissue is very unevenly developed, so that the 

 intrathecal regions may lie closely together or widely apart. 



There are twenty-six septa present in the majority of the 

 corallites, and the dilation of these at the theca extends for a 

 distance of about 1 mm. The dilation at the axial edge is but 

 feebly developed in this specimen. 



Longitudinal section. — The dissepiments are small and 

 crowded ; the tabulae are closely set. Shallow concave tabulae 

 occupy the central part of the intrathecal region, and these are 

 supplemented near the theca by smaller proximally-inclined plates. 



The figure should be compared with that of Aulina, p. 292. The 

 peripheral plates do not appear to be present in all species of the 

 genus. 



Notes upon Lonsdale's Figures and Statements. 



Fig. 3 combines a view of the weathered surface and the 

 longitudinally-polished face of specimen No. 6185. The features 

 displayed have been most accurately drawn, 1 and the portion 

 included in the figure can be precisely defined by a line. It is 

 evident that Lonsdale (and others after him) mistook the etched- 

 out interstitial calcite of the surface for actual coral-tissue. 



Fig. 3 b shows, on an enlarged scale, the longitudinal section 

 through a few septa as seen in the polished surface. It supplies 

 no useful information. 



"Fig. 3 a illustrates a transverse section, but, as has been pre- 

 viously mentioned, this figure has probably been supplied by 

 another specimen. The corallites are represented as being larger, 

 and the septa as being more numerous and more perfectly confluent, 

 than those in the specimen figured in fig. 3 a — the type. 



I have searched through the Daniel Sharpe Collection, and, 

 among those examined, the specimen with which the figure most 

 closely agrees is No. 6192, a thin polished slab of irregularly 

 pentagonal shape. In this specimen the theca? are larger (5 mm. 

 in diameter) and the septa are more numerous (about 36) than in 

 the t3 T pe-specimen ; and, furthermore, the dilation of the septa at 

 the theca is less localized and consequently not so obvious. The 

 characters displayed agree with Lonsdale's statements that there 

 are 36 septa (or rays, as he termed them), ' unequal in length 

 and breadth, and of a crenulated structure.' The last remark is 

 of some importance in identifying the specimen : it refers to a 

 feature not unfrequently found in mineralized corals, and is 

 strongly shown in the present ease — a feature due to the obli- 

 teration or partial obliteration of the dissepiments, except where 

 these meet the septa. Despite his assertion that the number of 

 septa is 36, Lonsdale only shows about 30 in this figure. The 

 origin of his fig. 3 a must, nevertheless, remain uncertain. 



1 The drawing is reversed on the plate, so that the right side in the original 

 is the left in the figure — a common occurrence in plates of the period. 



