PLEKOCHEILUS. 65 



Key to Species. 



a. Striped in zigzag or zebra pattern. 



b. Columellar fold very strong; peristome white; dark and 

 light stripes of equal width, aurissileni. 



bb. Columellar fold weak ; peristorae brown ; dark stripes nar- 

 row. 



c. Quite obese, spire short, blainvilleanus. 



cc. Slenderer, spire more produced, fulminant, 



act. Shell unicolored or without zigzag stripes, columella with no 

 fold of callus. 



[6. Uniform pink ; lip white or lilac, pudicus, antea, p. 6.] 



bb. Brown, the peristome brownish-orange, appuni. 



bbb. Streaked and spotted obliquely, higubris. 



P. AURISSILENI Born. PI. 22, figs. 57, 58. 



Shell ovate or obovate, perforate or umbilicate, solid and strong, 

 yellow or smoky-brown with longitudinal zebra-stripes of deep broivn 

 as wide as their intervals, and usually somewhat oblique or zigzag. 

 Surface finely sculptured with short, fine vertical wrinkles, cut into 

 spiral lines and bands by impressed spirals; and over this closely 

 malleated on the upper part of the body-whorl ; spire with close, 

 oblique riblets except earlier 2 whorls which are densely granulated. 

 Whorls slightly over 4, rapidly increasing, the last compressed at 

 periphery on its latter half. Suture shallow, becoming deeper and 

 obliquely descending on last whorl. 



Aperture vertical, ear-shaped, blue- or flesh-white inside; per- 

 istome well reflexed, white. Columella dilated above, adults bear- 

 ing a very strongly projecting, twisted, spirally entering fold above. 



Alt. 44, diam. 25$, alt. of aperture 28J mill. 



Island of tit. Vincent, West Indies. 



Valuta auris Sileni BORN, Test. Mus. Caes. Vindob., p. 212, pi. 9, 

 f. 3, 4. GMEL., Syst. Nat. (13), p. 3436. DILLWYN., Discr. Catal., 

 i, p. 502. Bulimus auris Sileni BRTJG., Encycl. Meth., i, p. 345. 

 KUSTER. Conchyl. Cab., p. 46, pi. 14, f. 3, 4. PFR., Monogr., ii, p. 

 87; iii,316; iv,380; vi, 23 ; Conchyl. Cab., pi. 22, f. 9. REI.VK, 

 Conch. Icon., pi. 25, f. 164. Auricula caprella LAM., An. s. Vert., 

 viii, p. 140. SOAVB., Conch. Man., f. 522, 523. Pupa caprella GRAY, 

 Ann. of Philos. n. ser., ix. p. 412. C'arychium undvlatum LEACH, 

 Zool. Misc. i, p. 37. Plekoche'dus undidatusGviL.DiyG, Zool. Journ. 

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