CRISIXA. 
177 
by cl’Orbigny ^ in 1849 for the Apsendesia dianthus of de Blainyille, 
which is a Bathonian species. The structure of lieticiilipora 
dianthus appears to me yery diflPereut from that of the Cretaceous 
species assigned to the genus. The Jurassic species is composed 
of closely packed zooecia, with suhpolygonal, crowded apertures, 
and of a numerous series of dactylethrse. The only resemblance 
between^, dianthus and the Cretaceous species called ^ ReticuUpora' 
is in the retifonn or pinnate shape of the zoarium. But as the 
zooecial characters are different, it seems necessary to separate the 
two groups into different fa mil ies. 
Fig. 13 . — Reticrisina ohliqua (Orb.). Middle Chalk. Chatham. Gamble Coll. 
D. 3956. Fig. 13a. — Vertical longitudinal section, x 26 dia. Fig. 13 — 
Horizontal transverse section, x 26 dia. 
In Reticrisina the apertures occur as long yertical rows, and 
the zooecia are monomorphic. In Reticulipora the apertures are 
limited to the obyerse edge, and the whole of the lower part of the 
branches is occupied by crowded, irregularly or quincuncially 
arranged angular zooecia, most of which are aborted to the condition 
of dactylethrae. The genus, in fact, resembles Retelea rather than 
Reticrisina. 
B’Orbigny clearly recognized the affinity of the Bryozoa that he 
figured as Reticulipora to Crisina ; he placed them in the same 
family, but separated them by their modes of growth. In Crisina., 
according to d’Orbigny, growth is only terminal ; whereas in his 
‘ Reticulipora ’ it is lateral as well as terminal. But at the distal 
ends of most Crisince there are fewer zooecia in the transyerse 
series than at the proximal parts of the zoarium. The increase in 
^ D’Orbigny: Eev. Mag. Zool. ser. 2, vol. i. p. 501. 
