﻿PAPILLATE MONTIPOR^. 81 



Calicles almost completely hidden from view, the apertures being arranged in the 

 angles at the bases of the papillse and looking mostly towards the growing edge and only 

 occasionally looking upwards, when the papiUce are not developed. Apertures from • 5 to 

 0'75 mm. in diameter, star-like, with two cycles of granular septa, the second cycle less 

 developed than the first. 



Coenenchyma, in section, shows the typical layer of outwardly streaming reticulum of 

 variable thickness, but usually very thin and passing both above and below into dense, solid 

 upper and lower layers of nearly equal thickness, and both of them thicker than the reticular 

 layer. The coenenchymatous papillse form hoods over the calicular apertures. The greater 

 part of the interstitial space itself is level, or even somewhat depressed. The hoods vary 

 greatly in size, from mere elevations slightly tilting the aperture to conical or cylindrical . 

 processes, with rounded tops rising 2 mm. high and measuring 2 mm. at the base. The 

 papillse show a tendency to form irregular concentric rows parallel with the edge. In 

 section, the papillse are seen to be hollow elevations of the solid upper layer. In the 

 interstitial spaces, the solid surface is beset with fine grannies. 



This is quite a unique type of Montiporan. The solidification of the upper thickening 

 layer, the papillse rising immediately behind the calicles and not occupying a more median 

 position in the interstitial space and thus forming hoods of solid matter over the calicular 

 apertures, are features which distinguish this type from all the others in the National 

 Collection. 



There are six specimens in all. Two are fragments which appear to have been parts 

 of a (circular?) concave plate, the larger fragment being 13 cm. long by 8 deep; neither 

 shows the method of attachment to the substratum. The growing edge of the larger 

 specimen appears to have begun to die down, being covered by a film. This is also an 

 unusual phenomenon, the centre being the region which as a rule first decays. This larger 

 fragment shows very slight traces of any epitheca, the under surface being formed by the 

 solid layer covered with small granules ; only a portion of a wrinkled epitheca is visible. 

 The smaller specimen is supported right to the edge by epitheca, which looks smooth and 

 glassy to the naked eye, but is very finely striated concentrically. 



a. Macclesfield Bank, China Seas, CoU. Bassett-Smith. (Type.) 



32 fathoms. 

 h. Apparently from the sam-e place. „ „ 



In addition to these there are two other specimens, one a large, rather crumpled fragment, 

 apparently of a very old stock, which difiers somewhat from the type. Upon the epitheca, 

 which is wrinkled, rests a thick solid layer, often tunnelled through by other organisms ; above 

 this occurs the reticular layer. The upper thickening layer, though very dense, is not 

 as solid as in the type. The whole corallum, too, is thicker and older, and the calicles are 

 consequently deeper and more conspicuous as dark holes. Their close association with the 

 papillse which rise up over them as hoods is, in this case, visible to the naked eye. 



These specimens are connected with a and h by the hood-like papillse ; they differ chiefly in 

 the less complete solidification of the upper thickening layer. It is possible that this solidifica- 



M 



