100 AUR1S. 



lete on the base, which is defined by a blunt keel ; earlier whorls 

 with strong but short subsutural ribs ; the latter 2 whorls with a 

 fine secondary sculpture of closely netted longitudinal wrinkles. 

 Apex white, somewhat obtuse, with a terminal comma-shaped pit. 

 Whorls 5. 



Aperture vertical, about half the shell's length, contracted, ear- 

 shaped, white or white and brown within; lip broadly reflexed, sin- 

 uous, white or ochraceous-brown ; the inner edge of lip and colu- 

 mella produced fonvard beyond the reflexion in a callous flange which 

 is continued upon the parietal wall to the upper angle of aperture, 

 and surrounds the cavity except for a sinus at the upper curve of the 

 outer lip. Columella ivhite, with a strong oblique fold ; parietal 

 wall white, ivith a yellow or ocJiraceons outer border. 



Alt. 48, diam. 29-31 mill. 



Brazil, at Bahia (Castelnau) and Ilheos (Moricand). 



Bulinus bilabiatus BROD. & SOWB., Zool. Journ., v, p. 49, suppl. 

 pi. 40, f. 1, 2 (1829). Bulimus bilabiatus DESK, in Lam., An. s. 

 Vert., viii, p. 261, (1838) ; and in Fer.,Hist., ii, p. 65, pi. 152, f. 6- 

 8. PFR., Conchyl. Cab., p. 35, pi. 5, f. 10, 11 ; Monogr., ii, p. 91 ; 

 iii, p. 371 (excl. var.); iv, p. 439 ; vi, p. 76. REEVE, Conch. Icon., 

 pi. 33, f. 201. HUPE in Anim. Nouv. ou rares rec. pendant 1'Ex- 

 ped. dans 1'Amer. du Sud, sous la direction du Compte F. de Castel- 

 nau, Moll., p. 58, pi. 6, f. 1, la. Helix maximiliana FER. in coll., 

 and of MORICAND, Mem. de la Soc. de Phys. et d'Hist. Nat. de 

 Geneve, vii, 1836, p. 431, ?pl. 2, f. 20, scalariform monstrosity (ex- 

 clusive of var. minor~). Partula maximiliana POT. & MICH., Gale- 

 rie des Moll. Mus. de Douai, i, p. 198, pi. 20, f. 5, 6 (1838). Pachy- 

 otus bilabiatus BECK, Index, p. 56. 



One of the most remarkable Bulimoid snails, peculiar in the 

 strong oblique ridges separated by concave intervals, and the erect 

 callous flange around the aperture. The sculpture is far stronger 

 than in the following species. 



Two forms occur, indistinguishable as to shape, but apparently 

 different in color at all stages of growth. Whether these are real 

 subspecies, or merely two phases of a single dimorphic stock, we 

 have no certain means of determining at present. The differences 

 are not due to age, the young shells also sharing them. 

 A. bilabiate typical. PI. 39, figs. 10, 11. 



Flange around the mouth and across parietal wall yellow, ochra- 

 ceous or white; outer edge of parietal wall yellow; columella and 

 parietal wall within the ffange white. 



