102 
BEEENICEA. 
Diagnosis. 
Zoarium small, reniform, thin ; sometimes piriform, OTong to 
the persistence of a short stalk-like proximal portion. 
Zooecia cylindrical, long, visible throughout their length. 
Peristomes irregularly and sparsely distributed ; highly raised. 
Dimensions. 
Disteibution. 
Upper Greensand : Cambridge. 
Eed Chalk : Hunstanton. 
PiGUKES. 
PI. Y. Pig. 3. A small zoarium, X 14 dia. Dpper Greensand: 
Cambridge. D. 2964. 
Affinities. 
This Bryozoan was first described by Vine in 1885 as Diastopora 
cretacea, Yine, var. lineata^ and subsequently in 1890 as Prohoscma 
jessoyii. The second specific name is accepted, since the species is 
different from ^ Biastopor a cretacea^^ Yine. The species appears to 
he a Berenicea rather than a Brohoscina, though it is one of the 
forms near the dividing-line between the two groups. 
Its nearest ally is the Cenomanian B. contracta, Seeley, from 
which it differs by the more uniform diameter of the zooecia, they 
being regularly cylindrical and not bottle-shaped. It closely 
resembles the young stage of B. dilmiana (Lam.) ; but comparison 
of Pigures 2 and 3 on PI. Y. shows that the young form of the 
Lower Greensand species has larger zooecia, while its peristomes 
are less raised. The last character, the thinness of the zoarium, 
and absence of the crowded peripheral zone separate it from 
B. confluens, which it may sometimes resemble, owing to' the 
reniform shape and similar distance of the peristomes in that 
Tjpe: 
Upper Greensand, 
Length of zooecia ... 1-1 *2 mm. 
Diameter of zooecia ... *2 ,, 
Diameter of apertures... •! ,, 
from Eed Chalk. 
E.M., D. 2025. 
Cambridge. 
D. 2964. 
•5-' 8 mm. 
species. 
