236 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



190S. Micropora coriacea ROBERTSON, The incrusting cheilostomatous Bryozoa of the west 

 coast of North America, University of California Publications, Zoology, vol. 4, 

 p. 275, pi. 17, fig. 26 (Bibliography). 



1909. Micropora coriacea NOBMAN, On the Polyzoa of Madeira, Journal Linnean Society, 



Zoology, vol. 30, p. 293. 

 Bibliography ( Paleontological ) . 



1862. Reptescharellina diaparilis GABB and HOKN, Journal Academy Natural Science, Phila- 

 delphia, ser. 2, vol. 5, p. 147, pi. 20, fig. 29. 



1S69. Membranipora gracilis REUSS, Die fossilen Anthozoen und Bryozoen der Schichten- 

 gruppe von Crosaro, Denkschriften der k. Akademie der Wisseuschaften, Wieu, vol. 

 59, Abth. 1, vol. 29. p. 291, pi. 29, fig. 13. 



1891. Micropora cnrinccn 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 Societe Beige 

 de Geologie, vol. 10, p. 365. 



1896. Micropora.. (Peneclausa) coriacea NEVIANI, Briozoi postpliocenici di Spilinga 

 (Calabrie), Atti Academia Gioenia di Scienze, Natural! in Cantania, ser. 4, vol. 9, 

 p. 17, fig. 3. 



1900. Micropora (Peneclausa) coriacea NEVIANI, Briozoi i neogeuici 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. S. p. 521. 



1906. Micropora r/racilis 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 In France, 

 Bulletin Socit 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 '//'.v/w/V/.v. 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. 



Variations. 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. 



f ^o=0.08 mm. . fZs=0.50-0.62mm. 

 Measurements. Opesium , /ooecium 7 



1 7(7=0.14 mm. U3=0.38mm. 



