PKOBOSCrXA. 
59 
Diagnosis. 
Zoariuni simple and long; of an iiTegular multiserial band, 
formed of from 6—8 zooecia in width, and broken up into 
segments by constrictions. 
Zooecia long ; in well-preserved specimens transversely wrinkled. 
The zooecia are faiidy straight or sinuous. 
Apertures large, irregularly distributed, and often so distant 
that the zooecia can be seen throughout their length. 
Peristomes slightly raised. 
Dimensions. 
Length of zooecia 
Diameter of zooecia 
Diameter of aperture 
Disteibution. 
Upper Greensand : Cambridge. 
? Gault : Barnwell, Cambridge. 
Bed Chalk ; Hunstanton. 
PiGITEES. 
PI. lY. Fig. Aa. Zoarium of Vine’s type of Prohoscina dilatata, 
var. cantahrigiensisy encrusting a RadioUtes ; nat. size. Fig. 4J, 
part of the same, X 10 dia. Upper Greensand: Cambridge. 
Lesson Coll. D. 2937. In other parts of the zoarium the sinuosity 
and transverse wrinkling of the zooecia are shown. 
Affinities. 
This ‘ species ’ presents a considerable resemblance to Prohoscina 
dilatata (Orb.), by the form of the zoarium and the size of the 
zooecia. But it differs from the French ‘ species ’ by the greater 
length of the zooecia and less crowded arrangement of the 
apertures. Pergens suggests that P. dilatata is perhaps the 
same as P. angustata, the dimensions being the same in both. 
P. hunstantonensis agrees better in this respect with P. ramosa 
(Edw.) than with P. angustata. 
Vine has described a variety of P. hunstantonensis with the name 
of ampliata. His type-specimen is in the Huseum collection, 
Type of var. cantabrigiensis. 
D. 2937. 
... 1‘3 mm. 
•25 „ 
•12 .. 
Type of 
hunstantonensis. 
1-4: mm. 
•2--25 ,, 
•1 
