BERENICEA. 
75 
The ‘ species ’ was extended to include Upper Cretaceous Bryozoa 
by von Reuss, who included in it some specimens from the Upper 
and Lower Planer of Bohemia. In 1872 the same author 
described his 1846 figure as “ec. mala''' and included it in the 
synonyms of B, grandis (Orb.), a proposal of doubtful value. 
Yon Reuss’ B. tenuis (non Orb.) may be regarded as an Upper 
Cretaceous representative of B. gracilis ; its main distinction is 
the somewhat smaller length of the zooecia. A typical Lower 
Greensand specimen and a representative of the var. tenuis are 
shown on PI. Y. Pig. 1 and PL IV. Pig. 6 respectively. The 
differences between them appear at first sight sufficient to make 
B. tenuis distinct ; but the differences in dimensions are inconstant 
and do not admit of definite numerical expression. That B. tenuis 
is not even a mutation, is shown by the fact that among the 
British specimens an Upper Chalk form is nearest in dimensions 
to Milne Edwards’ type. 
B. gracilis is a very typical member of the genus, and appears 
to be the Cretaceous representative of the type species B. diluviana^ 
Lamx.^ The close resemblance between them has been already 
pointed out in the Catalogue of Jurassic Bryozoa. 
Among Cretaceous species its nearest ally is B. papyracea 
(Orb.), which has much longer zooecia, though no sharp numerical 
separation can be drawn between them. 
The nearest Jurassic ally of this ‘ species’ is B. diluviana, Lamx.; 
the differences between them were referred to in the Cat. Jur. Bry. 
(p. 93), and in addition to those there noticed may be added the 
fact that in B. gracilis the zooecia are not so crowded on the 
margins of the zoarium. The specimen figured on PI. Y. Pig. 2 
is a young zoarium on a Zeilleria, which was labelled as a T. faba 
from the Lower Greensand ; the specimen was then figured to 
show how close the resemblance is between the young of B. gracilis 
and of B. diluviana. On re-examination of the specimen its 
affinities to the Jurassic species seemed so close that I asked 
Mr. R. B. Newton to redetermine the Zeilleria ; he recognized it 
as no doubt a specimen of the Cornbrash Z. ohovata. Hence there 
can be no doubt that the specimen is Jurassic, and had been 
erroneously included in the Cretaceous series. 
1 Cat. Jur. Bry. pp. 89-94, pi. iv. figs. 4, 6. 
