152 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
CALLOPORA AURITA Hincks, 1877. 
Plate 29, fig. 2. 
1877. Membranipora aurita Hincks, On British Poiyzoa, Annals and Magazine Natural 
History, ser. 4, vol. 20, p. 213. 
18S0. Membranipora aurita Hincks, British Marine Poiyzoa, p. 159, pi. 21, figs. 5, 6. 
1894. Membranipora aurita Levinsen, Mosdyr. Zoologica Danica, Hefte 9, p. 59, pi. 4, 
figs. 31-38. 
1902. Membranipora aurita Calvet, Bryozoaires des cotes de Corse, Travaux de ITnstituL 
de Zoologie de l’Universite de Montpellier, ser. 2, Memoire 12, p. 34. 
1909. Membranipora aurita Levinsen, Morphological and Systematic Studies on the Cheilo- 
storuatous Bryozoa, p. 150, pi. 9, fig. 4. 
1912. Membranipora aurita Osburn, The Bryozoa of the Woods Hole Region, Bulletin 
Bureau Fisheries, vol. 30. p. 230, pi. 23, fig. 37. 
Measurements . — Opesiajf 0 5*'“^ mm 
[fp == 0.10 mm. 
Zooecia 
\Lz= 0.25 mm. 
\lz— 0.17 mm. 
Affinities . — Only the single figured specimen has been found and unfortunately 
it is incomplete. The frontal of the ovicells is destroyed and the avicularia are 
inconstant. We think, however, that our determination of the species is correct. 
Our specimen is tubular, as it grew about a small alga at a bifurcation. Concerning 
this method of growth, Osburn wrote : “ Zoarium incrusting, usually on shell, but 
often on algae ... on the stems of algae the zooecia are generally irregular and 
the cells sometimes crowded.” 
The zooecial micrometric dimensions correspond exactly with those in Levin- 
sen’s figure. The opesial dimensions are very close to those which may be measured 
on the figure given by Hincks. 
In the vicinity of the two areal spines there is a contraction of the opesiiun. 
The same characteristic may be observed in Osburn’s figure. 
On many zooecia we have observed small avicularia in the same position as 
shown in the published figures, but they are not constant. They appear a little 
larger in the lateral portions of the zoarium. It thus appears very difficult to find 
any important differences between this fossil form and the recent Membranipora 
aurita Hincks. 
This species has hitherto never been found in the fossil state, and indeed, it 
was only recently discovered by Osburn in the West Atlantic. 
Occurrence . — Middle Jacksonian (Castle Hayne limestone) : Wilmington, North 
Carolina (very rare). 
Habitat . — North Sea: Off England and Denmark in the English Channel. 
Mediterranean. Eastern Atlantic: Azore Islands. West Atlantic off the coast of 
the United States. 
It lives at depths from 5 to 34 meters. However, at the Azores it has been 
dredged at a depth of 130 meters. 
Plesiotype. — Cat. No. 63919. U.S.N.M. 
