NORTH AMERICAN EARLY TERTIARY BRYOZOA. 533 



convex and formed of a tremocyst Avith very numerous pores placed on a very 

 finely perforated olocyst, from which it is separable. The apertura is formed of 

 a very large orbicular anter and of a narrower poster with proximal lip straight 

 and denticulated; the vestibular arch is clearly visible. The endozooecial ovicell 

 is immense and takes the place of a zooecium; it is convex and perforated with 

 tremopores; the apertura of the ovarian zooecia is much larger. Two auriculate 

 vibracula are placed symmetrically on the distal part of the zooecia. 



Measurements. Apertura Art = 0.25mm. . r/^=0.90-1.10mm. 



of ordinary zooecia la= 0.28 mm. ""' ia [7.?=O.SO-1.00mm. 



Apertura of | ha=0.25 mm. 

 ovarian zooecia V=0.35 mm. 



Variations. Numerous zooecia are closed at the level of the vestibular arch 

 by a sort of finely perforated operculum. They probably do not contain a polypide, 

 which perhaps died of disease. 1 The phenomenon is frequent in the family. The 

 two superposed frontals are clearly visible in figure 12; the tremopores are tubular 

 (fig. 11). 



The vibracula are quite constant. We think that the zoarium was not fixed 

 at the bottom of the seas,' that it was attached to the algae, and that the vibracula 

 assure stabilization. There were five septulae. 



Occu-rrence. Middle Jacksonian: Wilmington, North Carolina (common); 

 3J miles north of Grovania. Georgia (very rare). 



Upper Jacksonian (Ocala limestone) : Old Factory, H miles above Bainbridge, 

 Georgia (rare). 



Cotypes. Cat. No. 62604, U.S.N.M. 



Genus METRARABDOTOS Canu, 1914. 



1914. A[etraral>dotos OAXV. r.r.vuzoaires des Terrains clu Sud-Ouest de la France, Bulletin 

 SociSti? Gologique, France, vol. 14, p. 472. 



The ovicell is endozooecial. The apertura is semilunar, with a rimule and 

 lyrula. The frontal is surrounded with lateral areolae and formed of an olocyst 

 surmounted by a pleurocyst. 



Genotype. Metrarabdotos (Km-haw) monififeruiii Milne-Edwards, 1S36. 



Range. Priabonian-Astian. 



METRARABDOTOS MONILIFERUM Milne-Edwards, 1836. 



Plate OS, figs. 1-10. 



1S3C. KscJiarn Monilifcra MII.NI:- EDWARDS, lieeherches auatouiiqnes, physiologiques et zoo- 

 logiques sur les Escliares, Annales Sciences Nntunilles Zoologie. ser. 2, vol. 0. i>. 27. 

 pi. 9, fig. 1. 



1844. Eschara pvnctata PHILIPPI, Reitrage zur Kenntniss dor Tertiarversteinerungen des 

 nordwestlichen Deutschlands, pp. 38, 68, pi. 1, fig. 19. 



1 For the palcopnthology the reader should consult the following: 1913-1 Old. Dr. Rene Larger. La 

 centre evolution ou de'ge'ne'rescenee par 1'he'redite pathologique cause naturelle de 1'extinction des grmipes 

 animaux. Essai de palvopntholo^ie ^rnrral-i n.mpare'e, Bulletin et M^moires de la Societe 1 d'Anthropologie 

 de Paris, 1913. 



