236 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
1908. Micropora coriacea Robertson, The incrusting clieilostomatous Bryozoa of the west 
coast of North America, University of California Publications, Zoology, vol. 4, 
p. 275, pi. 17, fig. 2G (Bibliography). 
1909. Micropora coriacea Norman, On the Polyzoa of Madeira, Journal Linnean Society, 
Zoology, vol. 30, p. 293. 
Bibliography (Paleontological). 
1862. Reptescharellina disparilis Gabb and Horn, Journal Academy Natural Science, Phila- 
delphia, ser. 2, vol. 5, p. 147, pi. 20, fig. 29. 
1869. Memhranipora gracilis Reuss, Die fossilen Anthozoen und Bryozoen der Schichten- 
gruppe von Crosaro, Denkschriften der k. Akademie der Wissenschaften, Wien, vol. 
59, Abtli. 1, vol. 29, p. 291, pi. 29, fig. 13. 
1891. Micropora coriacea Waters, North Italian Bryozoa, Quarterly Journal of the Geologi- 
cal Society of London, vol. 47. p. 13, pi. 11, fig. 9. 
1896. Micropora coriacea Pergens, Bryozoaires des environs de Buda, Bulletin Societd Beige 
de Geologie, vol. 10, p. 365. 
1896. Micropora.. ( Peneclausa ) coriacea Neviani, Briozoi postpliocenici di Spilinga 
(Calabrie), Atti Academia Gioenia di Scienze, Naturali in Cantania, ser. 4, vol. 9, 
p. 17, fig. 3. 
1900. Micropora ( Peneclausa ) coriacea Neviani, Briozoi i neogenici delle Calabrie, Paleon- 
tographia italica, vol. 6, p. 166 (Italian bibliography). 
1904. Micropora coriacea Canu, Les Bryozoaires du Patagonien, Memoires Societe Geo- 
logique de France, vol. 12, No. 32, p. 10, pi. 1, fig. 15. 
1905. Micropora ( Peneclausa ) coriacea Neviani, Briozoi fossile di Carrubare (Calabrie), 
Bollettino della Societa geologica italiana, ser. 2, vol. 8, p. 521. 
1906. Micropora gracilis Canu, Bryozoaires des Terrains du Sud-Ouest de la France, I, 
Aquitanien, Bulletin Societe Geologique de France, ser. 4, vol. 6, p. 513, pi. 12, fig. 10. 
1910. Micropora coriacea Canu, Bryozoaires des Terraines du Sud-Ouest de la France, 
Bulletin Socidtd Geologique de la France, ser. 4, vol. 10, p. 845. 
This species has been known for a long time in America, where Gabb and 
Horn described it under the name of Reptescharellina disparilis. More recently 
Canu has noted it in the Patagonian of Argentina. In Europe, Waters observed 
the species in the Priabonian. As the living examples are found at Madeira and 
in the Gulf of Mexico, its presence in American Eocene strata was inevitable. 
Without ever being abundant it has been collected at a number of localities. 
We have already called the attention of the reader to this peculiarity of occur- 
rence, and we will later note still other examples. It is apparent that the course 
of the great Atlantic currents was at the end of the Eocene absolutely identical 
with that prevailing today. We lack bryozoan material from the middle Eocene 
in America and the lower Eocene in Europe, so that this problem can not be 
studied for the beginning of Eocene time. " 
V aviations. — The opesiules in the fossil forms of Micropora coriacea are often 
closed by fossilization. The ancestrula is unfortunately broken on the beautiful 
specimen from Wilmington, North Carolina, figured. The ovicell is endozooecial, 
but very prominent and always visible. The cryptocyst is smooth or very finely 
granulated. 
^=0.08mm. 
Measurements. — (Jpesium { 7 „ . . 
1 ] lo= 0.14 mm. 
Zooecium 
\ Zs = 0.50-0.62 mm. 
I lz— 0.38 mm. 
