NORTH AMERICAN EARLY TERTIARY BRYOZOA. 149 



Description. The zoarium incrusts pebbles. The zooccia are short, little dis- 

 tinct, separated by a narrow furrow ; the mural rim is thin, projecting but little, 

 convex, enlarged at the base ; the opesium is of the same form as the zooecium, a 

 little elliptical or nearly round. The hyperstomial ovicell, never closed by an 

 opercular valve, is globular and projecting; it is ornamented with a frontal callosity, 

 finely granular. There are two small avicularia at the base of each zooecium ; they 

 are, salient, triangular, and symmetrical. 



lf ,, . [^0=0.25 mm. - [3=0.35-0.40 mm. 



Measurements. Opesia 7 Zooecia 



1/0=0.15 mm. 1/3=0.25 mm. 



Occurrence. Midwayan (Clayton limestone) : Brundidge, Alabama (very 

 rare) . 



Geological distribution. Lutetian of Bavaria (Koschinsky) : Priabonian of 

 Vicentin (Waters) ; Stampian of Germany (Roemer, Reuss) ; Burdigalian of Gard 

 and of Herault in France (Collection Cnnu) : Helvetian of Italy (Seguenza), of 

 Gard and of Herault (Collection Canu) ; Zanclean of Italy (Seguenza) ; Plaisan- 

 cian of England (Busk), of Italy (Manzoni) ; Sicilian of Italy (Sequenza, Neviani) ; 

 Quaternary of Italy (Manzoni. Neviani) ; Miocene of New Zealand (Waters). 



Habitat. Eastern Atlantic from Madeira to Scandinavia. Mediterranean 

 and Adriatic. Dredged at about 150 meters, it lives chiefly from 10 to 40 meters. 



It is to be noted that the recent fauna of Madeira presents much relationship 

 to that of Florida. 



Plcsiotype.Q&i. No. 63793. U.S.N.M. 



CALLOPORA DUMERILI1 LATA, new variety. 



Elate 29, fig. 6. 



Our determination of this recent species in a horizon so low is the more remark- 

 able because in our large amount of material \ve have been able to discover only a 

 few specimens at Wilmington, much more distinct from the type and for which 

 we are obliged to make a new variety. 



Measurement*. Opesia 



A0=0.24 mm. . [Z3=0.30 mm. 



Zooecia (, 



/0=0.24-0.26 mm. 1/3=0.28 mm. 



A certain number of zooecia have only a single avicularium placed in front 

 of the opesium as in the genus Ramphonotus. On our specimens there is not a 

 single opesium resembling its neighbor. In general the elongated zooecia are less 

 common. For this reason we have believed that the American Jacksonian specimens 

 ought to be separated as a variety. The differences from the recent type-species 

 are slight, only the larger size of the opesia measuring 0.24 to 0.26 mm. instead of 

 0.20 mm., being an insignificant difference, for which reason it is useless to create 

 a new species. Moreover, there is almost a complete identity between our photo- 

 graphs and the varieties of Membranipora dumerilii figured by Busk. 1 



1 Crag Polyzoa, 1859, pi. 3. fig. 4. 



