MOLLUSCOIDEA. 333 



Biflustra disjuncta Gabb & Horn. 

 Plate XXIIL, Fig. 13. 



1862. Biflustra disjuncta G. & H., Jour. Acad. Nat. Sci. Phil., 



2nd ser., vol. 5, p. 153, pi. 20, fig. 37. 

 1864. BiHustra disjuncta Meek, Check List Inv. Foss. N. A., 



Cret. and Jur., p. 3. 

 1868. BiUurStra di'ijuncta Con., Cook's Geol. N. J., p. 722. 



Description. — Zoarium bifoliate, compressed. Zooecia robust, 

 elongate-hexagonal in outline, growing in longitudinal series and 

 arranged in quincunx ; the zooecia in each longitudinal series are 

 firmly united end tO' end, but the adhesion along the lateral mar- 

 gins and at the back is very slight. Zooecial apertures terminal, 

 oval, somewhat variable in form ; the floor of the zooecium sloping 

 upward in front and merging into the surface of the zoarium in 

 such a manner as tO' nearly or quite obliterate the anterior margin 

 of the aperture. Outer surface of the zooecia smooth, rounding 

 slightly inward to the aperture and to the constriction between 

 the apertures in the same longitudinal series. 



Remarks. — This species is one of the rarer forms, and has not 

 been met with in the recent collections. It was founded upon two 

 fragments only, and even these seem to have been lost or 

 destroyed. The characters of the species are such, however, if 

 the original description and illustration of Gabb and Horn are 

 a,ccurate, that it can be easily recognized should it be met with in 

 the future coillections. 



Fofmation and locality.— Timber Creek and near MuUica Hill 

 (Gabb and Horn). 



Geographic distribution. — New Jersey. 



Family MBMBRANIPORIDAB. 



Genus Amphiblestrum Gray. 



Amphiblestrum heteropora (Gabb & Horn). 



Plate XXIIL, Figs. 14-16. 



1862. ReptoHustrella ? heteropora G. & H., Jour. Acad. Nat. 

 Sci. Phil., 2d ser., vol. 5, p. 162, pi. 20, fig. 50. 



