774 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



1887. Idmonea milneana WATERS, Bryozoa from New South Wales, Annals Magazine Nat- 

 ural History, ser. 5, vol. 20, p. 256. 



18SS. Idmonea milneana WATERS, On some ovicells of Cyclostomatous Bryozoa, Journal 

 Linnean Society, London, Zoology, vol. 20, p. 279, pi. 14, fig. 8. 



1889. Idmonea milneana JELLY, A Synonymic Catalogue of the Recent Marine Bryozoa, 



p. 118. 



1890. Idmonea milneana. OKTMANN, Die Japanisclie Bryozoen-Fauna, Archiv. fur Nat- 



urgeschichte, vol. 1, Heft 1, p. 59, pi. 4, fig. 21. 



1905. Idmonea milneana WATERS, Bryozoa from near Cape Horn, Journal Linnean Society. 

 London, vol. 29, p. 249 (habitat). 



1908. Idmonea, milneana CANU, Bryozoaries fossiles du Sud-Ouest de la France, Bulletin 



Societe geologique France, ser. 4, vol. S, p. 386, pi. 7, fig. 16. 



1909. Idmonea milneana CANU, Bryozoaires tertiares des environs de Paris, Annals de 



Paleontologie. p. 125 (53), pi. 14, figs. 11, 12, 13. ( Paleontologic bibliography). 



1910. Idmonea milneana CANU, Bryozoaires fossiles du Sud-Ouest de la France, Bulletin 



Societe geologique de France, ser. 9, vol. 10. pi. 840. 



1911. Idmonea milneana CANU, Bryozoaires fossiles de Sud-Ouest de la France, Bulletin 



de la Societe geologique, ser. 4. vol. 11. p. 451, text, fig. 6. (ind. ). 



1914. Idmonea milneana WATERS, The marine fauna of East Africa and Zanzibar, Proceed- 

 ings of the Zoological Society of London, p. 844. 



Description. The zoarium is bifurcated, compressed with elliptical transverse 

 section broader than high. The fascicles are scattered, little salient, arranged alter- 

 nately on each side of the median axis; they are formed of three zooecia, the first 

 of which is isolated. The tubes are visible, convex, with thin peristome. The 

 basal lamella is convex, more or less striated transversally ; the tubes are visible 



longitudinally. 



fDiameter of the tubes 0.16-0.20 mm. 



I Distance between the fascicles... _ 0.40-0.60 mm. 



Variations. This species is rather constant in its characters and its determi- 

 nation is easy. We have not had the chance to discover its ovicell, but this has 

 been figured by Waters and Smitt ; it must probably occur very rarely. 



The width of the zoarium varies between 0.80 mm. (fig. 4) and 1.33 mm. 

 (fig. 3). The striations of the basal lamella are generally little deep; rarely they 

 are accentuated (fig. 5). 



The dorsal tangential section reveals the spindles characteristic of all the 

 cyclostomatous bryozoa in which the basal lamella is not reinforced (fig. 12). 

 The microscopic structure of the tubes is identical on the basal lamella (fig. 9) 

 and on the frontal face (fig. 8). The basal lamella has therefore no particular 

 reality; it results simply from the agglomeration of the tubes which are closely 

 united together. 



Occurrence. Middle Jacksonian (Castle Hayne limestone) : Wilmington. 

 North Carolina (very common). 



Vicksburgian (Red Bluff clay) : One-fourth mile west of Woodwards, Wayne 

 County, Mississippi (very rare). 



Geological distribution. Ypresiam of England (Gregory) ; Lutetian of the Paris 

 Basin (Gregory, Canu), of the Bordeaux Basin (Canu), of the French Pyrenees 



