NORTH AMERICAN EARLY TERTIARY BRYOZOA. 537 



guen/.a). of Belgium (Van den Broeck). Miocene of Australia (MacGillivray) 

 and of New Zealand (MacGillivray). 



PI, *;ot>/i>c*. Cat. No. 64316, U.S.N.M. 



METRARABDOTOS GRANDE, new species. 



Plate 98, figs. 11-15. 



Description. The zoarium is free, arborescent, branched dichotomously in the 

 same plane. The fronds are narrow, compressed, often twisted. The zooecia are 

 elongated, distinct, fusiform, the frontal is convex, surrounded by areolae, and 

 formed of a granular pleurocyst united to the olocyst. The apertura is oval and 

 formed of a semilunar anter and of a broad, triangular rimule. in which a very 

 small lyrula is placed. The peristome is hardly salient. The ovicell is endozooecial, 

 enormous, with a frontal ornamented with larger, radial costules. 



}ha=O.Wmm. . [2=0.90 mm. 



Measurements. Apertura , Zooecia- 7 nn 



lte=0.10mm. lfe=0.24 mm. 



Width of branches=3 to 5 mm. 



Variations. The zoarium bears some tuberosities (fig. !.">), partitioned in the 

 interior, which serve perhaps as zoarial hydrostatic apparatus. 



The frontal walls of the zooecium are very thick (fig. 15), whereas the lateral 

 walls are quite thin (fig. 14). 



This species is very abundant in the locality in Jasper County, Mississippi. 

 It alone numbers many more specimens than all the others combined and constitutes 

 almost alone the Cheilostome fauna of this locality. It occurs here in clay, which 

 habitat it seems to prefer. This is also the case in the MetrardbdotoB polymorphum 

 Eeuss, 1869, which lived in France in the clay of Gaas. 



We have attempted a restoration of this remarkable species ; the zoarium must 

 attain from 7 to 10 centimeters in length. 



Affinities. This species differs from Metrarabdotos monittferum Milne-Ed- 

 wards. 1836. in its longer zooecia (Z.3=0.90 instead of 0.60 mm.), in the absence of 

 small oral avicularia. and in a much larger zoarium, and with wider fronds (3-5 mm. 

 instead of 2 mm.). 



Occurrence. A 7 icksburgian (Marianna limestone) : Three miles southeast of 

 Vosburg, Jasper County. Mississippi (very common). 



Yicksburgian (Red Bluff clay) : Seven and one-half miles southwest of Bladen 

 Springs. Alabama (rare) ; Ecd Bluff, Wayne County. Mississippi (rare). 



Cotypes.Czt. No. 64317, U.S.N.M. 



Genus WATERSIPORA Neviani, 1895. 



1S95. Wutcnti/iorfi XEVIANI. Brioxoi neox.oici cli alcunp loeatitn d'ltalia. Bollettino ilelln 

 Societa Romaiiii per gli Studi Zoologici, pts. 2, 4, p. 231. 



The operculum is membranous or very slightly chitinous on the borders; it ex- 

 hibits a chitinous axial band of a brown color, marking out from the rest of the 

 operculum two lateral spaces, which are clearer and which correspond to the two 



