NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
585 
limited this genus to only those species whose ovicell is provided with a cribriform 
area. We are ignorant of the physiologic significance of this area, and we are 
unable to discuss the subject from a study of more or less well-preserved fossil forms. 
This species differs from Perigastreila tubulosa , which is also provided with 
a long peristomie, in its interareolar costules, and in its smaller micrometric dimen- 
sions (Liz— 0.45 and not 0.65 mm.). 
Perigastreila grotiani Reuss, 1865, is also provided with an exterior tubular 
peristomie, but our species differs in its more scattered areolae and in the presence 
of interareolar costules. 
It is to be noted that, this species does not spread out into flabelliform zoaria. 
We have observed it only on very narrow substrata, such as would be offered by 
the cyclostome bryozoa. It is not possible to comprehend how a wide substratum 
is capable of destroying larvae; we must therefore admit that a larva is capable 
of choosing its substratum, which is marvelous in the obscure depths of the sea. 
Such symbiosis is frequent everywhere in the bryozoa. 
Occurrence. — Vicksburgian (Marianna limestone) : West bank of Conecuh 
Ri ver, Escambia County, Alabama (common) ; Murder Creek, east of Castlebury, 
Alabama (very rare). 
Cotypes. — Cat. No. 61323, U.S.N.M. 
PERIGASTRELI.A? TUBULOSA, new species. 
Plate 74, fig. 1. 
Description. — The zoarium incrusts shells. The zooecia are distinct, long, 
lageniforin; the frontal is very convex, smooth, surrounded by very fine areolae. 
The apertura is deep, suborbicular, and formed of a large semilunar anter separated 
by two small cardelles from a very concave poster; the peristome bears six distal 
spines. The ovicell is smooth, globular, salient; it is hvperstomial, recumbent, 
opening largely in the peristomie ; it is surrounded by a very little salient collar. 
Measurements . — Apertura 
j/nz=0.13 mm. 
\la~ 0.13 mm. 
Zooecia 
Lz=0. 65 mm. 
lz= 0.30 mm. 
Affinities . — This species presents all the characters which would permit its 
classification in Lagenipora Hincks, 1888. However, its ovicell is not placed as 
in Lagenipora socialis Hincks, 1877, and does not bear the cribriform area noted 
by Waters. On the other hand, the apertura with cardelles is a little different 
from the semielliptical apertura of the other species of P erigastreUa. Finally the 
peristomiale is not free, which was a fundamental character according to Hincks. 
The generic place of this species is therefore doubtful. 
It differs from P erigastrellal costifera of the same lageniform group in its 
zooecial size (Zs=0.65 and not 0.45 mm.) and in its smooth frontal. 
Occurrence. — Upper Jacksonian (Ocala limestone) : Chipola River, east of 
Marianna, Jackson County, Florida (common). 
PLolotype.— Cat. No. 64204, U.S.N.M. 
