PLEUROCERA. 105 



ish line below the suture. The aperture is about one-third the length 

 of the shell. 



I have great pleasure iu naming this species after my friend Dr. 

 Spillman. — Lea. 



This species appears to me to be very closely allied to pyren- 

 elluni on one side aud to elevatum ou the other side. 



48. P. planogyrum, Anthony. 



Melanin plnnogyra, Antiioxy, Ann. Lye. N. T., vi. p. Ill, t. 3, f. 11, March, 1854. 

 BiNXEY, Check List, No. 207. Brot, List, p. 30. Reeve, Monog. Melania, 

 ep. 382. 



Description. — Shell conical, rather smooth, thick; of a dull, dark 

 horn-color, unrelieved by any other except a rather indistinct, brown 

 band, revolving near the base of each whorl, immediately below 

 which a raised, rounded, subcrenulated ridge revolves 

 between it aud the suture below; spire much but 

 not acutely elevated, with a nearly rectilinear out- 

 line ; whorls ten to eleven, flat or concave, and with 

 a well-impressed, channelled suture; aperture small, 

 rhomboidal, diaphanous, exhibiting the dark band of 

 the exterior through its substance very faintly, far 

 within ; columella deeply curved, not indented, thick- 

 ened at base; outer lip angularly curved, extended 

 forwards ; sinus rather broad, not deep. 



Diameter, -46 inch (12 millim.) ; length, 1-37 inches (34: millim.). 

 Length of aperture, --lO inch (10 millim.) ; breadth of aperture, •24 

 inch (6 millim.). 



Habitat. — Alabama. 



My cabinet. 



Observations. — A stout species which most resembles M. regularis, 

 Lea, in general appearance, from which, however, its concave whorls, 

 elevated carina, and dark band will readily distinguish it. It has 

 not the channelled body-whorl of M. canal iculata, Say, nor the con- 

 vex, subangulated upper Avhorls which distinguish that species. 



The lines of growth are very coarse and prominent, and extending 

 over the raised line near the base of the whorls, give the latter an 

 interrupted or subcrenulated appearance. — Anthomj. 



The figure is from the original type. 



