NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
149 
Description . — The zoarium incrusts pebbles. The zooecia are short, little dis- 
tinct, separated by a narrow furrow; the mural rim is thin, projecting but little, 
convex, enlarged at the base; the opesium is of the same form as the zooeeium, a 
little elliptical or nearly round. The hyperstomial ovicell, never closed by an 
opercular valve, is globular and projecting; it is ornamented with a frontal callosity, 
finely granular. There are two small avicularia at the base of each zooeeium; they 
are salient, triangular, and symmetrical. 
M easurements . — Opesia 
j 7m =0.25 mm. 
[7e>=0.15 mm. 
Zooecia 
| Zs= 0.35-0.40 
[Js= 0.25 mm. 
mm. 
Occurrence . — Midwayan (Clayton limestone) : Brundidge, Alabama (very 
rare). 
Geological distribution . — Lutetian of Bavaria (Koschinsky) ; Priabonian of 
Vicentin (Waters) ; Stampian of Germany (Roemer, Reuss) ; Burdigalian of Gard 
and of Herault in France (Collection Canu) ; Helvetian of Italy (Seguenza), of 
Gard and of Herault (Collection Canu) ; Zanclean of Italy (Seguenza) ; Plaisan- 
cian of England (Busk), of Italy (Manzoni) ; Sicilian of Italy (Sequenza, Neviani) ; 
Quaternary of Italy (Manzoni, Neviani) ; Miocene of New Zealand (Waters). 
Habitat . — Eastern Atlantic from Madeira to Scandinavia. Mediterranean 
and Adriatic. Dredged at about 150 meters, it lives chiefly from 10 to 40 meters. 
It is to be noted that the recent fauna of Madeira presents much relationship 
to that of Florida. 
Plesiotype. — Cat. No. 63793, U.S.N.M. 
CALLOPORA DUMERILII LATA, new variety. 
Plate 29, fig. 6. 
Our determination of this recent species in a horizon so low is the more remark- 
able because in our large amount of material we have been able to discover only a 
few specimens at. Wilmington, much more distinct from the type and for which 
we are obliged to make a new variety. 
M easurements . — Opesia 
\ho= 0.24 mm. 
(7<5=0.2T-0.26 mm. 
Zooecia 
\Lz= 0.30 mm. 
| Iz =0.2 8 mm. 
A certain number of zooecia have only a single avicularium placed in front 
of the opesium as in the genus Ramphonotus. On our specimens there is not a 
single opesium resembling its neighbor. In general the elongated zooecia are less 
common. For this reason we have believed that the American Jacksonian specimens 
ought to be separated as a variety. The differences from the recent type-species 
are slight, only the larger size of the opesia measuring 0.24 to 0.26 mm. instead of 
0,20 mm., being an insignificant difference, for which reason it is useless to create 
a new species. Moreover, there is almost a complete identity between our photo- 
graphs and the varieties of Membranipora dumerilii figured by Busk. 1 
Crag Polyzoa, 1859, pi. 3, fig. 4. 
