276 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



1845. Eschara digitata LONSDALE, Account of six species of Polyparia obtained from Timber 

 Creek, New Jersey, Quarterly Journal Geological Society of London, vol. 1, p. 73, 



figs, c, d, g (a and 6 ? exclus. e and /). 



1850. Eschara digitata D'OEBIGNY, Prodrome de paleontologie stratigraphique, vol. 2. p. 264. 

 1S62. Eschara digitata GABB and HORN, Monograph of the fossil Polyzoa of the Secondary 



and Tertiary formations of North America, Journal Academy of Natural Sciences 



of Philadelphia, ser. 2, vol. 5, p. 114. 

 1901. Eschara 1 digitata ULRICH, Maryland Geological Survey, Eocene, p. 216, pi. 60. 



figs. 11, 12. 

 1907. Onyclwcella digitata WELLER, Geological Survey New Jersey, Paleontology, vol. 4, 



p. 330. pi. 23, figs. 7-10. 



Description. " Zoarium bifoliate, branching dichotomously : branches flattened, 

 acutely elliptical in cross section, usually 2.5 to 3.0 mm. wide. Zooecia hexagonal, 

 regularly arranged in quincunx, about 0.55 long and 0.38 wide, bounded by a 

 slightly impressed line; surface concave, especially toward the aperture, which 

 is situated usually just in front of the center. Aperture semielliptical, rounded in 

 front, straight behind, 0.10 to 0.12 mm. wide. Normally developed and perfect, the 

 posterior border of the aperture is slightly raised and bears a delicate lunarium- 

 Jike curved plate, which extends into the aperture. Abortive cells, possibly of the 

 nature of vicarious avicularia, are frequent but seem to be entirely restricted to 

 the edges of the zoarium and to those portions lying just beneath the axes of 

 bifurcation. They are distinguished from the other cells by their subcircular and 

 usually smaller apertures. Ooecia unknown." (After Ulrich.) 



| ha= 0.15 mm. . [Zs = 0.60mm. 



Measurements. Aperture \ , ., _ Aooecium , . ... 



Ua=0,15 mm. (Z0=0.40mm. 



This species was discovered in the Eocene by Ulrich in 1901. The descrip- 

 tion which he gave is correct; nevertheless its "abortive cells" are the vibracula 

 of a perfect and well known type. 



The Eocene specimens are a little narrower than those of the Cretaceous at 

 Vincentown. 



Occurrence. Lowest Eocene (Bryozoan bed at base of Aquia formation) : 

 Upper Marlboro, Maryland (rare). 



Geological distribution. Upper Cretaceous (Vincentown marl=Danian) : 

 Vincentown and other localities in New Jersey. 



Plesiotypes.C*t. Nos. 63785, 63786. U.S.X.M. 



Genus MACROPORA MacGillivray, 1895. 



1895. Macroporri MACGILLIVRAY, Monograph Tertiary Polyza Victoria. Transactions Royal 

 Society Victoria, vol. 4, p. 54. 



"The zooecia very thick-walled, provided with pores, but without spines and 

 without opesiulcs. The zooecial structure is provided with a well-developed ves- 

 tibular arch. Ovicells and avicularia wanting, but among the zooecia we find 

 some which have an aperture of a different form and whose distal margin is fur- 

 nished with three membraneous feeler-like filament-. Dietellae." (Levinsen. 1909.) 



