﻿MONTIPOEA. 9 



reticular arrangement, and all mounting equally, merely thicken the corallum. The 

 calicles, which' also bend upwards, open on the level surface. 



(2) Foveolate. The reticulum may grow upwards faster than the calicles, in which case, 

 the interstitial spaces swell up as ramparts round the calicles, which consequently appear to 

 open in the bases of depressions or even of deep pits. 



(3) Papillate. The reticulum may grow faster than the calicles, but irregularly, so that 

 the interstitial spaces shoot up into papillEe of all sizes and shapes, and in many different 

 relations to the polyp cavities. 



(4) Tuherculate. Those threads of the thickening reticulum which stand at right angles 

 to the middle streaming layer become differentiated from the rest ; they straighten and thicken, 

 so that a vertical section of this layer, but of tliis layer alone, reminds one of the trabecular 

 coenenchyma of Pontes. All stages of this trabecular formation from the undifferentiated 

 reticulum can be traced. These trabeculse then rise above the interstitial spaces as spines 

 and cylindrical tubercles of different heights and variously arranged. The trabeculse, indeed, 

 may be looked upon as in reality the thickened submerged bases of protective surface tubercles. 



These, then, are the four primary divisions of the Montiporse as here classified. They 

 shade off into one another, the glabrous into the foveolate, the foveolate into the papillate, 

 owing to irregularities in the heights of the ramparts, and the papillate shade off into the 

 tuherculate by the diminution in the size of the papillse till they are but thickened single 

 threads. The specialisations are nevertheless quite clear and distinct.* 



Under each of these heads we may have any kind of growth, explanate, massive, or 

 ramose — indeed the same species in some cases appears under all these forms. 



* A word of explanation is necessary as to the restricted uses of the terms papillate and tuher- 

 culate here adopted. It was found absolutely necessary to distinguish between the papillate up- 

 risings of the reticulum of the interstitial spaces and the smaller solid spines rising from single 

 trabeculsB. The importance of this cannot be overestimated ; for in the types hitherto recorded, it 

 is, at least in many cases, impossible to tell from the description what was the true character of the 

 papillae mentioned. The old Montiporan type, papillosa de Blainville, seemed to justify the limitation 

 of the word " papillae " to the swellings of the reticulum as such. What, then, should the smaller 

 and more solid protuberances rising from single trabeculse be called ? In selecting the word 

 " tubercle," the present author was guided by certain indications which seemed to point to these 

 being the " tubercules " which characterised Lamarck's Pontes (Montipora) tuhermlosa. He writes : 

 " Ces tubercules graniformes ou columniformes dont sa surface est parsemee ' ; and again says, that 

 the interstices between the polyps of Ellis and Solander's M. foliosa are not " herissees de tubercules " 

 (' Animaux sans Vertebres,' 2nd ed. ii. (1816) p. 272. I think it must be admitted that these terms 

 are more apphcable to the " tubercles," as the word is here used, than to the large papilla. As a 

 matter of fact, examination of Lamarck's types, preserved in the Paris Museum, shows that they were, 

 small cylindrical papilla (see M. tuberculosa, p. 112) and not true tubercles as here defined. It is, 

 however, of no consequence whether one's reasons for adopting a term are sound or unsound, at least 

 in a case like this ; while, on the other hand, it is a great gain to have, for the future, clearly defined 

 meanings attached to the words used in the descriptions. 



C 



