NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
779 
1900. Idmonea atlantiea Neviani, Monographia del genere Idmonea Bryozoa Ciclostomata, 
pt. 1, pp. 6, 46 (synonomy) ; 1901, pt. 2, cap. 2, p. 74. 
1903. Idmonea atlantiea ■ Juli.ien and Calvet, Resultats des Campagnes scientifiques du 
Prince du Monaco, Fascicule 23, p. 113. 
1904. Idmonea atlantiea Waters, Bryozoa from Franz-Josef Land, pt. 2, Journal Linnean 
Society, Zoology, vol. 29, pp. 166, pi. 21, figs. 2, 3 (the ovicell here figured is un- 
usually short). 
1904. Idmonea atlantiea Waters, Bryozoa Resultats voyage Belgica, Zoologica, p. 90, 
pi. 9, fig. 5. 
1906. Idmonea atlantiea Nordgaard, Bryozoa from the 2d From Expedition, 1898-1902, 
Report Second Norwegian Arctic Expedition 1898-1902, No. 8, p. 38. 
1907. Idmonea atlantiea Calvet, Note par les expeditions du Travailleur et Talisman, 
vol. 8, p. 469. 
1909. Idmonea atlantiea Norman, The Polyzoa of Madeira and neighboring Islands, Jour- 
nal Linnean Society, Zoology, vol. 30, p. 278, pi. 33, figs. 1, 2. 
1912. Idmonea atlantiea Titornely, Marine Polyzoa of the Indian Ocean, Transactions 
Linnean Society, Zoology, ser. 2, vol. 15, p. 156. 
1912. Tubulipora atlantiea Osburn, The Bryozoa of the Woods Hole Region, Bulletin of 
the Bureau of Fisheries, vol. 30, 1910, p. 217, p. 19, figs. 9, 9a. 
1886. Tubulipora atlantiea, forma erecta Smitt, Kritisli forteckning ofver Skandinaivens 
Hafsbryozoer, Ofversigt af. Kongl. Vetenskaps-Akademiens Fordhandlingar. vol. 23, 
pp. 399, 434, pi. 3, figs. 6-7, pi. 4, figs. 3-13 (ovicell figured). 
1849. Idmonea radians Van Beneden, Recherches sur les Bryozoaires de la mer du nord 
(suite) et projet d’une classification des Bryozoaires, Bulletin l’Academie Royale 
de Belgique, vol. 16, p. 646, pi. 1, figs. 4-6. 
1916. Tubulipora atlantiea Harmer, The Polyzoa of the Siboga expedition, vol. 1, p. 124, 
pi. 10, figs. 4-5. 
Description . — The zoarium is free, linear, bifurcated, with subcircular trans- 
verse section. The fascicles are salient, quite removed from the median crest, 
arranged alternately on each side of it, much protruding beyond the zoarial mar- 
gins; they are formed of three to five zooecia the first of which is the longer and 
hides the others more or less. The basal lamella is somewhat striated longitudi- 
nally by the tubes, striated transversally by quite separated convex wrinkles; it is 
round or flat and more or less bordered laterally. The ovicell is much elon- 
gated, convex, scarcely lobecl, placed on the median crest among five or six fasci- 
cles. 
Variations . — The dorsal is round at the base of the branches (fig. 9) and flat 
on the younger branches (figs. 7, 8) ; the two forms are often visible on the same 
branch (fig. 4). The fascicles are quite fragile and break easily (fig. 6) ; but the 
fossils thus altered are exceedingly difficult of determination and are almost iden- 
tical with the linear branches of Idmonea petri D’Archiac, 1847. 
In a single instance only have we observed a very short radicell (fig. 10). 
The tangential (fig. 12) and longitudinal sections (figs. 11) offer no special 
features ; but the transverse section has a very special form, for it is almost circular 
or semicircular according to the form of the dorsal. 
Distance between the fascicles 0.48 (0.40-0.60 mm.). 
Width of the fascicles 0.14 mm. 
Width of the zoarium 0.60 (without the fascicles). 
