MIOCENE MOLLUSCA AND CRUSTACEA. 135 



Genus MONILEA Swainson. 



MONILEA (LeiOTROCHUS) EBOREA, 



Plate XXIV, figs. 7-10. 



Trochus ehoreus Waguer : Joiir. Acad. Nat. Sci. Phila., Ist ser., vol. 8, p. 52, PL I, 



fig. 5. 

 Monilea {Leiotroch) eborca, Com-ad: Proc. Acad. Nat. Sci. Phila., 1862, p. 569; Meek, 



Check List Miocene Foss., p. 15. 

 Turbo eboreus, Heilprin : Proc. Acad. Nat. Sci. Phila., 1877, pp. 398 and 404. 



"Shell smooth and slightly polished; spire short, conical; whorls flat- 

 tened laterally, margined above by a very obtuse obsolete carina; spiral 

 lines obsolete; periphery sharply augulated, subcariuated; Ijase flattened, 

 siibumbilicated ; columella grooved; aperture half the length of the shell." 

 (Wagner, loc. cit.) 



This is one of the most beautifiil fossil shells of the New Jersey Mio- 

 cene formation. It is of small size, being not more than three-eighths of 

 an inch m height, and having the greatest transverse diameter a little exceed- 

 ing the height. The form is broadly conical, the spiral angle being always 

 within ninety degrees, but sometimes almost reaching that angle. Volutions 

 six in number, in the largest specimens, including the nuclear whorl, their 

 sm-faces polished and flattened in the direction of the spire, the last one being 

 a little convex; periphery subangular with a. slightly raised keel just above 

 it, which shows as a raised band above the sutures of the upper volutions. 

 There are also fom- or five raised spiral lines on the last two volutions and 

 sometimes appearing even above that point; also fine transverse lines of 

 growth mark the sm-face. Faint spiral lines also appear sometimes on the 

 lower sm-face, which is very moderately convex. Aperture transverse, 

 oblique, columella curved and thickened, with a single obsolete denticle 

 near the base. Umbilicus closed. 



Formation and locality: Dr. Wagner's specimens came fi'om the Mio- 

 cene deposits along the Patuxent River, Maryland. The New Jersey spec- 

 imens are from the gray marls of the same deposits at Jericho, N. J., where 

 the shell appears to have been moderately common in comparison with 

 most of the species. The specimens used are from the collections at the 

 National Museum, and were collected by Mr. Frank Bm-ns. 



