110 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
In the present state of bryozoology, generic grouping in distinct families 
quite frequently is necessarily artificial, arbitrary, and problematic, since we lack 
anatomical and larval data in most 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. 
Genus VIBRACELLINA Canu and Bassler, 1917. 
1917. Vibracellina Canu and Bassler, Synopsis of American Early Tertiary Cheilostome 
Bryozoa, Bulletin 96, United States National Museum, p. 14. 
Endozooecial ovicell. Auriform vibracula. No cryptocyst. No dietellae. 
Genotype. — Vibracellina capillaria Canu and Bassler, 1917. 
With the exception of Cupuladna we know three species of Membranipores hav- 
ing auriform vibracula. These are VibraeeUa trapezoidea Reuss. 1844, very well 
described by Waters, 1 who has created for it the genus Vibracella; Pyripora con- 
fluens Canu, 1907 (not Reuss, 1844), which is probably the type of a new genus 
and Vibracellina capillaria , Canu and Bassler, 1917. 
In 1890 Kirkpatrick figured an incrusting species M embranipora hastilis from 
the China Sea, of which he wrote : “ Placed transversely at the head of each 
zooecium are ear-shaped vibracular cells, toothed on one margin, with a vibraculum 
shaped like a double-edged spear.” Some months later he declared he was mis- 
taken and that his Membranipora hastilis was the same as M embranipora, coronata 
Hincks. We think that he has been misled in the place occupied by the avicularium. 
That of Membranipora coronata is triangular and not auriform. The two species 
appear to us distinct and M. hastilis might be of the type of our genus Vibracellina. 
VIBRACELLINA CAPILLARIA Canu and Bassler, 1917. 
Plate 16, fig. 16. 
1917. Vibracellina capillaria Canu and Bassler, Synopsis of American Early Tertiary 
Bryozoa, Bulletin 96, United States National Museum, p. 14, pi. 1, fig. 5. 
Desci'iption.- — The zoarium incrusts small shells. The zooecia 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 inter - 
zooecial, unsymmetrical ; its opesium is oblique and bounded by two lips of which 
the upper one is convex and sinuous. The ovicell is a distal convexity. 
Affinities. — At the center of the figured zoarium may be noted two smaller 
zooecia almost equal; which of these is the ancestrula can not be discerned. It 
is also to be noted that, excepting these, the zooecia assume their normal size almost 
immediately. The absence of the cryptocyst and the almost complete absence of 
the gymnocyst will distinguish this species easily from Pyripora confluents Canu, 
1907 (not Reuss, 1844). 
Occurrence.- — Claibornian (Cook Mountain formation) : Moseleys Ferry, Cald- 
well County, Texas (rare). 
Holotype.- — Cat. No. 62572, U.S.N.M. 
1 Waters, North Italian Bryozoa, Quarterly Journal Geological Society, London, vol. 47. p. 10, pi. l 
Eg. 23. 
