MARYLAND GEOLOGICAL SURVEY 227 



grooves, giving the shell somewhat of a cancellated appearance." Conrad, 

 1830. 



Length, 38 mm. ; diameter, 28 mm. 



Occurrence. — St. Mary's Formation. St. Mary's River. 



Collections. — Maryland Geological Survey, Philadelphia Academy of 

 Xatural Sciences. 



Family CYPR/EID/E. 



Genus ERATO Risso. 



Erato perexigua (Conrad). 

 Plate LV, Fig. 5. 



Mar ginella perexigua Conrad, 1841, Proc. Acad. Nat. Sci. Phila., vol. i, p. 33. 

 Marginella perexigua Conrad, 1843, Jour. Acad. Nat. Sci. Phila., vol. viii, 1st sen, 



p. 189. 

 ? Erato kevis^ 1 Emmons, 1858, Kept. N. Car. Geol. Survey, p. 362, fig. 139. 

 ? Erato Maicger ice Emmons, 18.58, Rept. N. Car. Geol. Survey, "Additions and 



Corrections." 

 Volutella sp. Dall, 1893, Trans. Wagner Free Inst. Sci., vol. iii, pt. ii, p. 336. 

 Volutella sp. ?iov. Harris, 1893, Amer. Jour. Sci., ser. iii, vol. xlv, p. 34. 

 Erato Emmonsi Whitfield, 1894, Men. xxiv, U. S. Geol. Survey, p. 108, pi. xix, 



figs. 9-11. 



Description. — " Very small, obtusely ovate ; labrum profoundly thick- 

 ened, the margin minutely crenulated; labium with 4 plaits; spire 

 depressed; volutions concealed. 



" A small species very much like a Cypraea in form. Length one- 

 eighth inch." Conrad, 1842. 



Whitfield describes the form from the New Jersey Miocene as follows : 



" Shell small, strongly obovate, swollen or inflated above, and con- 

 tracted in the lower part; spire short or very obtuse, slightly coated so 

 as to render the suture indistinct ; aperture narrow, not quite as long as 

 the body of the shell. Outer lip thickened outwardly and in the medial 

 portion of its length on the inside and below, but scarcely so above; 

 strongly crenulated over all the thickened parts, bearing ten distinct 

 ridges on the only perfect example seen. Inner lip bearing four distinct 



1 Emmons' species has been generally known by this name. Everyone seems to 

 have overlooked the fact that Emmons himself in the ^^ Additions and Corrections'' at 

 the end of the volume changed the determination to Erato Maugerice. 



