MOLLUSCOIDEA. 335 



1864. Membranipora plebia Meek, Check List Inv. Foss. N. A., 



Cret. and Jur., p. 3. 



1868. Membranipora plebeia Con., Cook's Geol. N. J., p. 723. 

 1896. Membranipora plebeia Ulrich, Zittel-Eastman Text Book 



of Pal., p. 287, fig. 478. 



Description. Zoarium encrusting, growing upon shells, echi- 

 noids and other bryozoans. Zocecia in a single layer, from .3 

 mm. to .4 mm. in length, their width about two-thirds the length, 

 usually with a quincunxial arrangement, the adjacent ones sepa- 

 rated by a distinct depressed line which sometimes widens so as 

 to form small open spaces. Zocecal apertures elliptical or ovate 

 in outline, large, leaving a very narrow zocecial wall. Ovicells 

 variable in their distribution, sometimes abundant, but usually 

 much scattered. Avicularia few in number. 



Formation and locality. Vincentown limesand, Vincentown 

 (154), near Mullica Hill (Gabb and Horn). 



Geographic distribution. New Jersey. 



Membranipora annuloidea Ulrich and Bassler n. sp. 

 Plate XXIII., Fig. 18. 



Description. Zoarium encrusting. Zocecia from .5 mm., to 

 .65 mm. in length, their width about three-fourths their length, 

 more or less hexagonal in outline, sharply defined by depressed 

 furrows. Zocecial apertures about .2 mm. in length, subovate in 

 outline, surrounded by a rather broad, somewhat elevated, 

 rounded marginal rim which is marked by a series of from 10 to 

 13 small subcircular pits with raised borders. Ovicells variable 

 in their distribution, either abundant or much scattered, usually 

 a little broader than long with the side next the zocecial aperture 

 somewhat flattened, about .15 mm. in width. 



Remarks. This species is rather rare at Vincentown. When 

 worn, the marginal ring of pits about the zocecial apertures are 

 more or less obscure and sometimes wanting entirely. The species 

 somewhat resembles the Italian Tertiary species M. annulus Man- 

 zoni, 1 but differs in having more rounded zocecia and more 

 numerous pores. 



1 Bryoz. Foss. Ital., 4th Contrib., p. 7, Tav. i, fig. 6. 



