MOLLrUSCOIDEA. 339 



Planicellaria cylindrica Gabb & Horn. 

 Plate XXIV., Pig. 8. 



1862. Flustrella cylindrica G. & H., Jour. Acad. Nat. Sci. Phil., 



2d ser., vol. 5, p. 161, pi. 20, fig. 49. 

 1864. Flu^strella cylindrica Meek, Check List Inv. Foss. N. A., 



Cret. and Jur., p. 4. 

 1868. Flustrella cylindrica Con., Cook's Geol. N. J., p. 723. 



Description. — ^Zoarium consisting of cylindrical or oval ( ?) 

 branches, with six longitudinal rows of zooecia in the type speci- 

 men, arranged in quincunx. Zooecia divided externally into two 

 subequal regions; the anterior region convex and oval, with its 

 longest diameter the greater, pierced in its center by a circular 

 or oval aperture whose diameter is about one-third the width 

 of the zooecium ; the posterior region is flatter and supports a sub- 

 quadrate labiate process, probably the point of attachment of an 

 avicularium, which is depressed behind and elevated in front; it 

 is truncated above so that the opening is directed forward and 

 upward. 



Remarks. — This species resembles the last, differing chiefly in 

 the smaller number of rows of zQoecia. 



Formation and locality. — Vincentown limesand, near MuUica 

 Hill (Gabb and Horn), Vincentown (154). 



Geographic distribution. — New Jersey. 



Genus EscharineIvLA d'Orbigny. 



Escharinella altimuralis tririch and Bassler n. sp. 



Plate XXIV., Figs. 9-10. 



Description, — Zoarium encrusting, zooecia subrhomboidal in 

 outline, about 0.5 mm. in length, with very thin walls. At each 

 angle is a rather large avicularium, subcircular or subelliptical in 

 outline, with walls somewhat thicker than those of the zooecia. 



Remarks. — This is a very distinct species, abundant at Vincen- 

 town, which may be easily recognized by its thin walls and 

 prominent avicularia. 



