Mr. II. J. Carter on the Strom atoporidEB. 311 



My observations on Caunopora 'placenta have been manifold ; 

 and up to my last commmiication on the subject I had always 

 alluded to it under the name of " Stromatopora " (' Annals,' 

 1878, vol. ii. p. 85). This having been explained, then, let 

 us proceed to a description of the fossil dissected out of a cal- 

 careous laminated amorphous mass from the Devonian Lime- 

 stone, about two feet (and probably more originally) in 

 diameter. 



Here it is composed of large nodules growing from different 

 nuclei and enveloping during its spreading course more or less 

 foreign material and the petrified remains of many foreign 

 organisms. Taking one of these nodules about three inches 

 in diameter (for they vary in size above and below this 

 measurement), we find it hemispherical or parabolical; and 

 commencing with a horizontal section through the base, the 

 central or axial part is observed to be composed of a cribriform 

 structure,occasioned by the presence of a tubulated coenenchy ma, 

 to be more particularly described presently, of which the ends 

 of the tubes in juxtaposition are alone here visible ; outside 

 which, extending to the circumference, is a curv{linea>' ccenen- 

 cliyma (that is, curvilinear in the element, as already described 

 in Millepora alcicornis) through whicli tuhes at a variable 

 distance from each other radiate from the axial structure to 

 the circumference, intermixed with rods of opaque white 

 calcite taking the same direction, which are intimately con- 

 nected with the curvilinear fibre of the coenenchyma, of which 

 they, indeed, form part ; while they are composed of a more 

 transparent calcite internally, which would lead to the supposi- 

 tion that they were once hollow, did not the same differentiation 

 appear in the cojnenchymal tissue between the tubes in the 

 " axial structure " of the living Millepora alcicornis^ as before 

 stated. Further, these radiating se])arated tubes are more or 

 less divided into compartments by fahulce ; and here and there, 

 along the lines of concentric laminae which they traverse, and 

 which cliaracterizc the structure generally, are seen circular 

 spaces indicative of vertical sections of horizontal vessels, which 

 we shall presently find, by the indications of the previous 

 existence of stelliform groups of the hydrophyton-vessels on 

 the surface, to have existed between the laminoe respectively. 



If we now make a vertical section through tiie axis of the 

 cone, the same structure will of course present itself externally, 

 while the axial structure, consisting of tubes in juxtaposition 

 radiating upwards and outwards, will come into view longitu- 

 dinally, when they will be found to have been so numerously 

 perforated with holes and traversed by tahulw, tliat, at first, 

 I was inclined to think this specimen of CaunojJora had grown 



