10 
CRETACEOUS CILIOPOUA 
it, and I believe that it is fav pi’eferable to many of the crael combinations intro- 
duced by d’Orbigny. 'VYhat I have stated regarding the variations of growth 
of Celleiwra, chiefly depending upon the form and character of the foreign sub- 
stances on which it groAVs, equally applies to Biscopora and to Memhranipora. 
IVith the former, therefore, Beptescharinella must evidently he united, and the 
distinction of Semiescham, Semiescharinelki,* Semieschar ellina, (in part) and of 
some others, is very doubtful, for the same reason which 1 noticed when speaking 
of Cellepora. 
8. Membranipora, Blainvillc, 1831. 
Cells widely open in front, the facial surface remaining solid only to a small 
extent near the base, except in very old cells, which gradually become entirely 
closed ; colonies incrusting foreign substances in single layers. 
The Membraniporce are numerous in nearly all the formations, in which Cheilo- 
stomata occm’, and also in the present seas, but the determination of the fossils is 
occasionally accompanied with a great amount of uncertainty ; for in many in- 
stances the aspect of the cells enthely depends upon the state of preservation, and 
in others the injiu’ed cells of Celleporce are hardly to be distinguished from some 
Membraniporce. 
Besides this the amount to which the originally horny or chitinous cell be- 
comes calcareous seems to vary both according to age as well as individually and 
locally, as I have illustrated at length in Membranipora Bengalensis,-\ above 
referred to. 
D’Orhigny’s Flustrellaria, Semijlustrella, Laterojlustrella, BeptoJlustrella, 2 in{\. 
similar combinations of Flustrina are very doubtfully separable from Membranipora. 
9. Fluslrella, d’Orb., 1852. 
Cells solid, more or less confluent Avith each other, provided with an elongated, 
sub-central, almost slit-like aperture, and usually one or Iaa'o elevated tumid 
pores beloAV it. Colonies ramose, compressed, with the cells arranged in longitu- 
dinal alternating series on two sides of the compressed branches. The cretaceous 
F. poiymorpha, d’Orb., may be considered as one of the characteristic species of 
this genus. Several of the species described by d’Orbigny under Fkistrina a.p- 
pear also to belong to this genus, but others are to be referred to one or the other 
of the two following genera. 
10. Fscharinella, d’Orb., 1852. 
Cells depressed, surrounded by raised margin, with the facial surface solid and 
pierced in the anterior portion Avith a transversely elongated or semi-ovate aperture ; 
* D’Orbigny’s Mtdtescharinella, (like so many others beginning with &c.,) 
is a purely imaginary thing, for Keuss’ Cellepora prolifera, for which the new generic name was employed, is a 
peaceable Celleporaria. 
t AVhen Prof. Lenkart complained of the imperfect description which I gave of this species, he does not appear 
to have been aware that he had merely the absti-aet of the paper before him, (Comp. Troschel’s Archiv, vol. 35, pt. ii, 
p. 341), but when he suggests the probable identity with Hislopia, it only shows how little my friend was at that time 
acquainted with the latter genus. 
( 44 ) 
