GASTEROPODA OF THE LOWER GREEN MARLS. -119 



Genus ALARIA Morris. 



Alaria rostrata. 



Plate XIV, Figs. 5-6. 



Rostellaria rostrata Gabb: Jour. Acad. Nat. Sci., Phila., 2d ser., vol. 4, p. 390, 



PI. Lxviii, Fig. 7. 

 Gladius rostrata Gabb: Synopsis, pp. 55, 77. 



Anchura rostrata (Gabb) Meek: Gaol. N. J., Newark, 1868, p. 729. 

 Anchura (DrepanocMlus) rostrata (Gabb) Meek, Check List Cret. and Jur. Foss. , 

 p. 19. 



Shell of only moderate size ; spire elevated, forming an apical angle of 

 about 35°, but somewhat variable in different specimens; whorls about six 

 in number, very slightly convex between the sutures, which are not very 

 strongly marked, and are ornamented by rather closely arranged vertical 

 folds, smaller, more numerous, and more closely arranged on the upper than 

 on the body whorl; those on the last whoid become smaller, shortei*, and 

 more indistinct toward the expanded lip, on the back of which they become 

 obsolete; on all the upper whorls the folds extend from suture to suture, 

 but on the last one they are marked only on the upper or larger parts ; outer 

 lip expanded, forming a broad, wing-like extension which is jDrolonged below 

 along the moderately long rostral beak, and above is extended into an- 

 obtusely pointed hook-like process from its outer upper border. This fea- 

 ture I have seen enthe only on the type specimen, though several are before 

 me which show the expansion of the lip. No keel-like ridge marks the 

 back of the lip, as in most of the species of this group from the Cretaceous 

 beds of the Upper Missouri region. 



This species may be distinguished from the others of the group from 

 New Jersey bynts smaller size, smaller and more closely arranged vertical 

 folds, and proportionally shorter and more obtuse spire. There appears to 

 be a very great degree of variation among the specimens of this species in 

 the proportions of the spire, some of them being very much more slender 

 than the rate of increase mentioned above. There is also considerable 

 difference in the strength and number of the vertical folds, but none of them 

 approach in coarseness that of the most nearly allied forms associated with 

 it- in New Jersey, from which this feature alone will readily distinguish it. 



Formation and locality : In the brown layers of the Lower Marls near 

 Burlington, New Jersey, where it appears to be a somewhat common species. 



