north' AMERICAN LATER TERTIARY AND QUATERNARY BRYOZOA. 37 



Genus OGIVALINA Canu and Bassler, 1917. 



(For descriptioa see Bulletin 10(3, U. ^. Xational Museum, p. 117.) 



OGIVALINA MUTABILIS Canu and Bassler, 1919. 



Plate 1, fig. 3. 



1919. Ogivalina mutaUlis Canu and Bassler. Geology and Paleontology of the West Indies, Bry- 

 ozoa, Publication Carnegie Institution of Washington, No. 291, p. SO, pi. 1, fig. 4. 



Description.— The zoarium is incrusting. The zooecia are elongated, oval, 



distinct, separated by a deep furrow; the mural rim is thin, smooth, rounded; there 



is often a small gymnocyst. The opesium is very large, irregular, more often oval. 



The ovicell is endozooecial, small, little convex. Sometimes there is a small inter- 



zooecial fusiform avicularium ( ?) 



^ . fAo = 0. 60-0 70 mm. y ■ fL2 = 0. 75-0.95 mm. 

 Measurements. ~-O^Qs\& \j^^q 30-045 mm. -^ooeua j ^^^^ 50-0.70 mm. 



The great irregularity of form and zooecial dimensions of this species occasions 

 its name." There are some variations which recall those of llembranipora irregularis 

 Manzoni, 1875,' which possesses a mural rim enlarged at the base and also some large 

 interzooecial avicularia. 



The present species differs from the splendid Ogivalina eximipora Canu and Bas- 

 sler, 1917, from the Middle Jacksonian in its smaller dimensions, in the absence of 

 cryptocyst and in the presence of a gynmocyst. The avicularium ( ?) is identical in 



form and position. 



Occurrence. Upper Oligocene fEmperador limestone) : Old quarry, one-third 



mile north of west of Empire, Panama Canal zone (rare) . Upper Oligocene (AnguiUa 

 formation) : Southwest side Crocus Bay Hill, Anguilla, Leward Islands (rare). 



Eolotype.—C&i. No. 68443, U.S.N. M. 



OGIVALINA PARVULA Ulrich and Bassler. 1904. 



Plate 12, fig. 6. 

 1904. Memhranipora parvula Ulrich and Bassler, Bryozoa, Maryland Geological Survey, Mio- 

 cene, p. 310, pi. Ill, fig. 1, 2. 

 The original description of this species is as follows: 

 In its general zoarial and zooecial characters this species resembles Memhranipora ^^rmana Ulrich 

 and Bassler, 1904 and J/. pZefteia Gabb and Horn, but it is readily distinguished by the smaller size and 

 less elongate form of its zooecia. The walls are also relatively thicker while the longitudinal arrangement 

 of the zooecia is more pronounced. Measuring longitudinally, 8 zooecia occur in 3 mm. and transversely 

 12 may be counted in the same space. 



To the above we would add that there is a small gymnocyst and that the ovicell 

 is endozooecial and the avicularium is interzooecial. 



Occwrrence— Miocene (Calvert formation) : Reed's Maryland (rare.) 

 Holoty'pe.—G&t. No. 68444, U.S.N.M. 



5 Briozoi del pUocene antico di Castrocaro Bologna, 1S75, p. 10. pi. 1, Sgs. 5, S. 



