DESCRIPTION OF CHALK CORALS. 29] 
De Blainville (op. cit. p. 408), and has been admitted into subsequent syste- 
matic works. In the ‘ Manuel d’Actinologie’ three species are mentioned, Aps. 
cristata', Aps. dianthus*, and Aps. cerebriformis*. The first, M. Lamouroux’s type, 
apparently consists, according to M. Michelin’s beautiful delineations, of lamelli- 
form branches progressively united by a dorsal layer, the upper edges and the 
extremities being free; and the whole forms broad, leaf-like expansions with a 
jagged margin. M. De Blainville states that the pores ‘‘ existent au bord méme des 
lames ou crétes ;’’ but on the free reverse extremities of M. Michelin’s fig. 5 d, 
pores are as evident and are extended nearly as far backwards as on the crests 
(fig. 5¢). No information respecting the characters of the apertures, except that 
the pores are ‘‘ plus ou moins alveoliformes ” (Man. d’Act. p. 409), or of the 
internal structures, has been published, though the genus has been invariably 
associated with true Anthozoa. It is almost needless to observe, that Lamouroux 
totally misunderstood the nature of the fossil described by him (consult De BI. 
loc. cit.). Aps. cerebriformis is excellently represented in the ‘ Iconographie 
Zoophytologique*,’ and the author of these memoranda is indebted to M. Miche- 
lin for a labeled specimen of the coral. It consists, as will be seen by reference 
to the quoted figures, of convoluted bands composed of vertical tubes, which open 
only along the crests, the sides being covered by a continuous, thin layer without 
a vestige of a mouth. The tubular cavities have no furrows or other represen- 
tatives of lamella, but they are crossed, as abundantly shown in the specimen 
received from M. Michelin, by transverse plates deemed a sufficient proof of the 
fossil having been constructed by an anthozoan polype. A comparison of 
figures 5a, 5b, 5c (Icon. Zoophyt. pl. 55) with figures 5 a, 56 (ibid. pl. 75) will 
raise doubts whether Aps. cristata and Aps. cerebriformis are generically identical ; 
but so far as concerns the present inquiry, this is a question of little consequence, 
only a small amount of agreement being detectable between the chalk fossil and 
Aps. cristata, and none whatever between it and Aps. cerebriformis, or with the 
other species, provided that zoophyte has been rightly assigned to the class An- 
thozoa. So great indeed is the difference, that attention would not have been 
* Lamouroux, Exp. Méthod. doc. eit. in note *: also Man. d’ Actinol. pl. 65. fig. 3, and Icon. Zoophytol. 
pl. 55. f. 5a; 6, ¢. 
* Man. d’Actinol. pl. 69. fig. 2; Icon. Zoophytol. pl. 55. fig. 4a, 8, e. 
* Ieon. Zoophytol. p. 314. pl. 75. fig. 5a, b. 4 
* Ibid. p. 314. pl. 75. fig. 5 a, b: consult also M. Milne-Edwards’s remarks on Aps. cerebriformis, 
Lamarck, edit. 1836, t. ii. p. 290. : 
