288 DESCRIPTION OF CHALK CORALS, 
Pustulopora pustulosa, De Blainville 2 and Michelin. 
(Tab. XVIII. A. figs.8 & 8ato8h.} 
Tubular, dichotomously branched ; apertures to visceral cavities merely termi- 
nations of tubes, near together, more or less pustulous, arranged in annular rows 
or irregularly distributed ; area of cavities circular, gradually contracted down- 
wards ; parietes thick, defined by a faint translucent line. 
Ceriopora pustulosa, Goldfuss? Petref. p. 37. pl. 11. f.3. Maestricht. 
Pustulopora pustulosa, De Blainville ? Man. d’Actinol. p. 418. 
—-—, Michelin, Icon. Zoophyt. p. 211. pl. 53. f. 4. Grés vert 
des environs du Mans. 
Judging by external characters, the fossil delineated in Tab. XVIII. A. fig. 8, 
bears a great resemblance to the greensand coral of M. Michelin; but an 
agreement with Prof. Goldfuss’s representations of the one found at Maes- 
tricht is considered less evident. The visceral cavities of M. De Blainville’s! 
original species of Pustulopora are represented, with one exception, as simple, 
elongated hollows in the substance of the coral; and the species subsequently 
added by M. Milne-Edwards’ have apparently a similar composition. The excep- 
tion just mentioned, Pust. radiciformis (Goldf. tab. 10. f. 8), exhibits in a transverse 
fracture (fig. 8c) several distinctly rounded tubes, and M. Edwards? says, ‘‘ je doute 
beaucoup que le Ceriopora radiciformis présente intérieurement le mode propre 
aux Pustulopores.”” One of Mr. Dixon’s specimens afforded an analogous cross- 
section (fig. 8a) ; but it could not be regarded as a proof that the branch consisted 
of perfectly separable tubes, the rounded sides at the lines of contact being 
cemented together ; other transverse fractures (fig. 8 b) presented also as little ap- 
pearance of such a composition as the quoted delineations of M. Goldfuss, unless 
attention was particularly directed to indications of that structure, and even then 
they were not visible except under a proper light, depending on faint translucent 
lines ; while a worn termination of what had been a natural extremity (fig. 8 c) 
gave not a sign of a tubular composition. It is therefore plain that the characters 
exhibited by a fracture depended on the nature of the intersection ; and probably 
1 Man. d’Actinol. p. 418. Consult Goldfuss’s delineations of Ceriopora madreporacea, tab. 10. 
f.12 a, b, and C. pustulosa, tab. 11. f. 3 a, b. 
* Mém. sur les Crisies, &e., Ann, Se. Nat. 2nde sér. Zool. t. ix. pl. 11. f. 4. pl. 12. f.1,2; or Re- 
cherches sur les Polypes. 
* Ibid. M. Edwards (Ann. Se. Nat. oc. cit.) likewise objects to C. verticillata being referred to 
the genus, regarding it as rather “d'un genre particulier voisin des Spiropores de Lamouroux, Cri- 
copora, De Blainville.” 
