MOLLUSCOIDEA. . 345 



Pormation and locality. — Vincentown limesand, Timber Creek 

 (Gabb and Horn). 



Geographic distribution. — New Jersey. 



Family MIOROPOBIDAB. 



Genus RepToporina d'Orbigny. 

 Reptoporina carinata Gabb and Horn. 



i860. Cellepora carinata G. & H., Proc. Acad. Nat. Sci. Phil, 



i860, p. 366. 

 i860. Cellepora carinata Gabb, Jour. Acad. Nat. Sci. Phil, 2d 



ser., vol. 4, p. 400, pi. 69, figs. 24-26. 

 1862. Reptoporina carinata G. & H., Jour. Acad. Nat. Sci. Phil., 



2d ser., vol. 5, p. 144. 

 .1864. Reptoporina carinata Meek, Check List Inv. Foss. N. A., 



Cret. and Jur., p. 3. 

 1868. Reptoporina carinata Con., Cook's Geol. N. J., p. 722. 

 1905. Cellepora carinata Johns., Proc. Acad. Nat. Sci. Phil., 



190S, P- S- 



Description. — Zoarium encrusting. Zocecia sharply defined, 

 elongate-hexagonal, the sides straight, the proximal end nar- 

 rowest, arranged in regular quincunx. Zocecal apertures anterior 

 in position and directed obliquely forward, ovate to subquadrate 

 in outline, proximal margin straight or concave (sometimes with 

 a median tooth projecting forward?). Outer surface of the 

 zocecia carinate along the median line or rarely rounded, the 

 carina reaching its highest point a little back of the aperture, 

 from which point the surface slopes downward in front to the 

 proximal margin of the aperture. Upon the sloping surface 

 between the highest point of the outer zocecal wall and the proxi- 

 mal margin of the aperture, is a small pore which doubtless in- 

 dicates the position of an avicularium. 



Remarks. — This species may be distinguished from any of its 

 associates by the elongate-hexagonal, usually carinate zooecia, 

 with the avicularia situated just back of the proximal margin of 

 the aperture. 



