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 Cupuladria we know three species of Membrani pores hav- 

 ing auriform vibracula. These are Vibracella 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 Membranipora has tills 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 Membranipora 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. o. 



Description. 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 a Iso 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 confluens Canu, 

 1907 (not Reuss, 1844). 



Occurrence. Claibornian (Cook Mountain formation) : Moseleys Ferry, Cald- 

 well County, Texas (rare). 



Holotype.GvA. No. 62572, U.S.N.M. 



1 Waters, North Italian Bryozoa, Quarterly Journal Geological Society, London, vol. 47. p. ]0. pi. i 

 Bg. 23. 



