386 
SPAESICAVEA. 
PL XIII. Fig. 6. A brancli witb a gonocyst, X 10 dia. Upper 
Chalk : Croydon. Old Coll. D. 4479. 
PI. XIII. Fig. 7. A branch of foim francqana with gonocyst, 
X 10 dia. Middle Chalk; Chatham. Giamble Coll. D. 432. 
Fig. 49. A longitudinal section, X 14 dia. Middle Chalk: 
Chatham. Vine Coll. D. 2703. 
Fig. 49 . — Sparsicavea carantina. Orb. Longitudinal section. 
Affinities. 
The two forms carantina and francqana as figured by d’Orbigny 
look extremely distinct ; they were united by Pergens, who 
regarded the figure of the latter as exaggerated. But, as Vine 
has remarked, it fairly represents some of the Chatham specimens. 
The occurrence, however, of both types in different parts of the 
same zoarium, in Chatham specimens, as shown on PI. XIII. 
Fig. 1, shows the justice of Pergens’ decision. 
The species is chiefly allied to S. orhignyi^ from which it differs 
by the absence of the bare terminal zones. The character of the 
ends of the branches is shown in the specimen D. 436 : the radial 
ribbing is not developed, and the apertures occur surrounded by 
scattered maculse. 
LIST OF SPECIMEXS. 
British. 
D. 695. A fragment of a zoarium showing transition from the irregular and 
distant apertures to regularly spiral arrangement. Middle Chalk. 
Chatham. Vine CoU. Figd. PI. XIII. Fig. 1. 
D. 2623. Two branches (on slide). One shows the occurrence of both, ribbed 
and punctate ornamentation in the same specimen. Middle Chalk. 
Chatham. Vine Coll., No. 28. Recorded by Vine as Entalophora 
madreporaeea, Goldf. : Rep. Brit. Assoc. 1892, p. 309. Figd. 
PI. XIII. Fiff. 2. 
