68 PALEONTOLOGY OF NEW JBESEY. 



pointed in some individuals. There is a considerable degree of variation 

 among the individuals, both in the form and in the proportional length of 

 the tubes, some of the casts being cylindrical and others flattened laterally 

 on the posterior half They appear to have burrowed in wood or in other 

 substances indiscriminately, many of them showing unmistakable evidences 

 of a woody structure on the outside of the cast of the tube; while one 

 colony which I have seen had burrowed into the shell of Gervilliopsis ensi- 

 formis. 



Formation and locality. — In the Lower Green Marls near New Eg}-pt, 

 and at Mr. Ware's pits near Mullica Hill; and at Hunt's pits at Manal- 

 apan, Monmouth Count}', New Jersey. There are several individuals in 

 the collection of the Academy of Natural Sciences, Philadelphia, which 

 would appear to have come from several other localities, but they are only 

 marked "N. J.," no more definite locality being known. 



PTERIIDtE Meek {—Aviculidoe of Authors). 



Genus PTEKIA Scopoli. 



Pteria petrosa. 



Plate XIV, Fig. 10. 



Avicula j)etrosa Courad. Jour. A. N. S., Phil., 2d ser.. Vol. II, p. 274, PI. XXIV, Fig. 



15. Gabb, Synopsis, p. 102. 

 Pteria petrosa (Con.). Meek, Checklist Smith. Inst., p. 9. 

 Comp. Avicula laripes Morton. Synop. Cret. N. Am., p. C3, PI. XVII, Fig. 5. 



Shell of moderate size, obliquely ovate, unequivalve, very inequilateral, 

 and moderately ventricose; hinge-line straight, its entire length being un- 

 known, and so far as can be determined from the imjDerfect casts examined 

 has not been extended in form of a wing posteriorly. Anterior wing of 

 considerable size and separated from the body of the shell by a deep con- 

 striction, most distinct on the right valve, and protruding beyond the beaks 

 of the shell anteriorly. Surface of the cast of the right valve preserving 

 indications of a few distant radii along the umbonal slope, but none are 

 visible on the left valve, probably owing to the greater thickness of the 

 shell not transmitting them to the interior surface. 



