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. Biflustra disjuncta Meek, Check List Inv. Foss. N.- A., 



Cret. and Jur., p. 3. 

 1868. Biflustra disjuncta Con., Cook's Geol. N. ]., p. 722. 



Description. Zoarium bifoliate, compressed. Zocecia robust, 

 elongate-hexagonal in outline, growing in longitudinal series and 

 arranged in quincunx ; the zocecia 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 

 accurate, that it can be easily recognized should it be met with in 

 the future collections. 



Formation and locality. Timber Creek and near Mullica Hill 

 (Gabb and Horn). 



Geographic distribution. New Jersey. 



Family MEMBRANIPOBIDAB. 



Genus AMPHIBLESTRUM Gray. 



Amphiblestrum heteropora (Gabb & Horn). 



Plate XXIIL, Figs. 14-16. 



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

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



