ART. 22. CYCLOSTOMATOUS BRYOZOA CAKU AND BASSLER. 



25 



The tetragonal aspect of the zoarium is more an optical effect result- 

 ing from the arrangement of the tubes, for it does not show ver\' 

 clearlv in transA^erse sections. 



Fig. 4. — Bisidnionea tetragona Laiuoiiroiix. 



A. Part of a branch, X 4, showing arrangemeut of the lubes. (After Gregory, 

 1896.) 



B, C. D"Orbign.v\s diagrammatic views of a branch and a cross section, em- 

 phasizing the tetragonal sliape. 



D. Transverse section, X 16. 



E. Longitudinal section, X 16. The walls are vesicular in the expanded parts 

 of the tubes. The latter are closed by a facette perforated by the aperture. 



Jurassic (Bathonian) : Ranville (Calvados). France. 



Oocurrence. — Jurassic (Bathonian) : Kanville (Calvados), France. 

 Plesioty pes. —Cat. No. 68916, U.S.N.M. 



BISmMONEA? GLOBULOECIA. new gpecieg. 



Plate 3, figs. 7-10. 



Description,. — The zoarium is quadrangular and formed as if two 

 specimens of hhvonea were joined by their dorsal; the fascicles are 

 formed of three tulies and arranged alternately on each side of the 

 zooecial area. The figure given Ijy D'Orbigny is entirely too regular, 

 thread ; the peristome is thin, elliptical, salient. The ovicell is a large 

 orbicular sack, quite globular.^ smooth, very salient, broad as a zoarial 

 face ; the oeciostome is anterior and little transverse. 



(Diameter of peristome 0.17 mm. 



,, ^ Distance between fascicles .32 mm. 



vVidth of branches .60 mm. 



Diameter of ovicell .35 mm. 



