310 DESCRIPTION OF CHALK CORALS 
That genus was proposed by M. Goldfuss for numerous zoophytes, and he 
ascribed to it the following leading characters :—enveloping layers of cells, the 
cells being tubular or sub-prismatic, sub-contiguous, paraliel or diverging (Petref. 
p- 32). The name Ceriopora has been retained by M. De Blainville, M. Milne- 
Edwards, and other authorities, but limited by the first to four’, and by the second 
positively to only two? of the original species ; one of those regarded by M. Ed- 
wards as doubtful has been also removed by Prof. Goldfuss to Stromatopora 
(Petref. p. 215, observations on Strom. polymorpha). M. De Blainville’s charac- 
ters, adopted by M. Milne-Edwards, are poriform, round cells, irregularly distri- 
buted, and forming by their union and accumulation in concentric layers a cal- 
careous, polymorphous coral. One of the retained species (Cer. micropora), as 
delineated by Prof. Goldfuss’*, consists evidently of concentric strata (loc. cit. 
fig. 4 b), conformable to each other, and composed of oval cells (fig. 4) ; the 
terminating apertures being round (fig. 4 d), and so far as can be ascertained they 
constitute direct openings into the cells: no secondary pores are represented, 
the small interspaces having apparently a solid composition. Another species 
absolutely retained, Cer. polymorpha (op. cit. pl. 10. f. 7a to 7d and pl. 30. fig. 11), 
presents diversities of form; but the layers are stated to be not thicker than 
paper (p. 34, obs.), and the cells are said to be round and of equal dimensions 
(pl. 10. fig. 7d) ; the apex of the warts also to be hollow (pl. 10. fig. 7 6). The 
structural objections mentioned with reference to Cer. micropora apply equally 
to this coral. M. De Blainville’s last species, Cer. compressa (Goldf. pl. 11. 
f. 4a-4b), is not retained by M. Milne-Edwards, and it presents peculiarities 
of composition, which would require a careful investigation before its true nature 
could be determined. 
If the characters of the Ceriopore noticed in the preceding paragraph be com- 
pared with those of the English chalk fossil, numerous essential differences will 
be evident. The surface-openings in M. Goldfuss’s figures are uniform in size 
(pl. 10. f. 4d, pl. 10. f. 7d); it is likewise stated as respects Cer. polymorpha, 
that the ‘‘cells”’ (apertures) are of equal dimensions (p. 34). M. De Blainville 
moreover proposed the genus Heteropora for certain Ceriopore, which have ‘‘ two 
sorts of pores”’ (Man. d’Actinol. p. 417). The chalk fossil has clearly two sets, 
' Man. d’Actinol. p. 413. 
* Lamarck, 2nd ed. 1836, t. ii. p. 313. Consult Observations on Cer. verrucosa. 
* Op. cit. tab. 10. f. 4 to 4d, also Man. d’Actinol. pl. 70. f. 2, for representations of the original 
figures 4a, 4d. 
