90 PROCEEDIIS^GS OF THE NATIONAL MUSEUM 



VOL. 70 



MATHILDA GRANIFEBA, new species 



Shell small (immature) , with a translucent smooth inverted nucleus 

 of a whorl and a half and six subsequent whorls; suture constricted, 

 appressed; axial sculpture on the two earlier normal whorls of close- 

 set small ribs crossing the whorls; spiral sculpture is gradually initi- 

 ated by (on the following whorls one, on the later whorls two) series 

 of prominent gi-anules developed by spiral grooving, and there is a 

 small plain thread in front of the suture; the base is marginated by 

 a small beaded thread with a minute plain one on each side of it, 

 within this margin it is marked with radial feeble ridges; aperture 

 rectangular with a sharp angulation in front of the very short pillar. 

 Length of shell, 3; of last whorl, 1; diameter, 1.3 mm. U. S. Nat. 

 Mus. Cat. No. 108356. 



Off Georgia, one specimen. 



The sculpture is so peculiar that it seemed desirable to describe 

 this specimen in spite of its immaturity. 



MATHILDA AMAEA, new species 



Shell minute, creamy white, with an inverted nucleus and about 

 five and a half well-rounded subturrited subsequent whorls; suture 

 distinct, deep; spiral sculpture of (on the early whorls two, on the 

 later ones three) small cords and another on the last whorl on which 

 the suture is laid, in front of which the base is nearly smooth; all 

 these except the last are obscured by the dense axial sculpture of 

 strong equal and equally spaced threads with narrower interspaces 

 crossing from suture to suture and not giving the aspect of reticula- 

 tion; base slightly flattened, imperforate; aperture rounded with 

 thin margins. Length of shell, 4.5; of last whorl, 2.5; diameter, 

 2.3 mm. U. S. Nat. Mus. Cat. No. 108089. 



Off Fernandina and Georgia, common. 



This except for the nucleus has much the look of the Epitonium 

 to which the name Amaea has been applied. 



MATHU.DA RUSHII DalL 



Mathilda rushii Dall, Bull. Mus. Comp. Zool., vol. 18, p. 267, 1889. 



Shell small, slender, subturrited, white, with a minute half im- 

 mersed nucleus, and about nine subsequent moderately rounded 

 whorls; suture distinct, deep; spiral sculpture of, on the spire two, 

 on the last whorl three very obscure cords near the periphery, on 

 the anterior one of the last whorl the suture is laid, within which the 

 base is nearly smooth; axial sculpture of numerous strong threads, 

 extending from suture to suture with narrower interspaces, almost 

 hiding the spirals which do not nodulate the axials at their inter- 

 sections; base imperforate, aperture short, rounded, with thin margins. 



