28 
PEOBOSCINA. 
Aitinities. 
This species is here accepted for Proloscmce which have zooecia 
similar to those of S. gracilis, hut have a crowded zoarium with 
the ends of the branches collected into fan-shaped tufts. 
The first difficulty in the treatment of this ‘ species ’ is the 
question whether M. Edwards used the name for the same form 
as did his predecessor de Blainville. This is very doubtful. 
De Blainville’ s figure was very diagrammatic and imperfect; but 
so far as its evidence goes, it was apparently intended to represent 
the form for which M. Edwards founded the ‘ species ’ Stomatopora 
gracilis. However, it would only lead to confusion to invert the 
names from their accepted use, and thus it seems most convenient 
to regard Milne Edwards as the founder of both ‘ species,’ 
dismissing the figure of the earlier author as indeterminable. 
This course is the more reasonable since de Blain\dlle gave no 
diagnosis of his Alecto ramea. 
The species is closely allied to P. angustata^ but differs from 
it by the multiserial ends of the branches. In the specimen 
figured on PI. II. Fig. 2, the tufted ends of the zoarium include 
as many as six. zooecia in a single width. But the younger part 
of the colony is barely distinguishable from P. angustata. 
Another close ally is P. hagenoivi (Rss.), which differs by the 
extreme irregularity of the zoarium ; its branches are at first 
uniserial, become irregularly multiserial, and then may contract 
again into biserial or uniserial branches. 
LIST OF SPECIMENS. 
D. 2976. On Galerites albogalerus. Tipper Chalk. Kent. Bowerbank Coll. 
Figd. PL II. Fig. 2. 
D. 2941. "With Stomatopora granulata and Epiphaxum auloporoides, Lonsd. , 
on Micraster coranguinum. Upper Chalk. Sussex. Dixon Coll. 
The type of Eiastopora wetherelli, Lonsdale, in Dixon’s Geol. 
Suss. p. 320, pi. xviii. fig. 35; pi. xviii. a, figs. 3, 3o. A badly 
preserved young specimen, with very slender zooecia. 
D. 3246. Encrusting fragment of Echinocorys (on sHde). Upper part of the 
zone of BeUmnitella mucronata. Upper Chalk. Clarendon, near 
Sahshury. Presented by Dr. H. P. Blackmore, F.G.S. 
D. 4870. Encrusting an echinid fragment (on shde) . Upper Chalk. Charlton. 
Presented by G. C. Crick, Esq., F.G.S. 
D. 3855. Encrusting an echinid fragment (on slide). Middle Chalk. Chatham. 
Gamble CoU. 
D. 364. Encrusting an echinid fragment (on slide). Middle Chalk. Chatham. 
Gamble Coll. 
