14 BULLETIN 96, UNITED STATES NATIONAL MUSEUM. 



least two pairs of large lateral septulse to each zooecium and only one 



l)air in the vibraculum. 



,, , ^ . fAo=0.12nini. 



Measurements. — Opesium , ..„ 



^ [lo=0.10 mm, 



„ . fZ,s=0.25mm. 

 Zoceciumj ^^^^,20-0.27 mm. 



^r•^ 1 fZ ^'=0.25 mm. 

 Vibraculum , _ . „ 



[ /y =0,10 mm. 



Occurrence. — Claibornian: Claiborne, Alabama (common). 

 Lower Jacksonian: Jackson, Mississippi (common). 

 T7/pe.— Cat. No. 62571, U.S.N.M. 



SECTION II. MEMBRANIPORAE WITH ENDOZO(ECIAL OVICEII. 



We liaA'e recognized four genera of Membranipores provided 

 with an endozooecial ovicell, a structure which distinguishes them 

 from genera of the first section quite as clearly as from those which 

 have a hyperstomial ovicell. Furthermore, these four genera do not 

 appear to belong even to the same family. 



Vibracellina may perhaps belong to the Lunulariidae. 



Einchsina, according to Norman, is a member of the Flustridae. 



Ogivalina is possibly a member of the Onychocelliclae. 



Memhrendoecium may perhaps be referred to the Farciminariidae. 



In the present state of bryozoology, generic grouping in distinct 

 families quite frequently is necessarily artificial, arbitrary, and prob- 

 lematic since we lack anatomical and larval data in many cases. It 

 is better therefore to maintain these four genera in the present place 

 rather than to introduce them doubtfully into the recent families 

 mentioned above. 



VIBRACELLINA, new genus. 



Endozocecial ovicell. Auriform vibracula. No cryptocyst. No 

 dietellae. 



Genotype. — Vibracellina capillaria, new species. Claibornian. 



VIBRACELLINA CAPILLARIA, new species. 

 Plate 1, fig. 5. 



Description. — The zoarium incrusts small shells. The zocecia are 

 elongate, distinct, oval, with a very small gymnocyst ; the mural rim 

 is convex, salient, very thin, almost capillary. The opesium is oval, 

 entire. The vibraculum is interzocecial, unsymmetrical ; its opesium 

 is oblique and bounded by two lips of which the upper one is con- 

 vex and sinuous. The ovicell is a distal convexity. 



Affinities. — At the center of the figured zoarium may be noted two 

 smaller zocecia almost equal; which of these is the ancestrula can 

 not be discerned. It is also to be noted that excepting these, the 



