MACKODONT. 31 



M. ODONTOSTOMUS (Sowerby). I J 1. 13, tigs. x5, si'., 87. 



Shell ri mate- perforate, pylindric-fusiform, solitl, uniform light 

 chestnut-brown ; surface somewhat glossy, densely and sharply stri- 

 ated obliquely, and seen under a lens to be closely cut by spiral lines. 

 Whorls about (5^, convex, rapidly increasing, the last becoming fret- 

 in front, impressed behind the outer lip. with three pits in the im- 

 pression, the latter half of the base pinched into a very strong though 

 blunt keel, defining a flat basal area, pitted behind the lip, and sepa- 

 rated from the umbilical excavation by a shorter keel. Umbilical 

 cavity ample. Aperture oblique, oblong, obstructed by 8 lamclhi 

 and folds: a marginal, triangular tooth on the straight parietal mar- 

 gin, an oblique, slightly calloused columellar plication, crossed below 

 by a transverse columellar lamella, a blunt, low-conic basal fold, and 

 within tbe outer lip three compressed folds, the median (upper pala- 

 tal) obliquely descending as it passes inward, the lower palatal en- 

 tering, the suprapalatal small. Peristome pink or lilac-tinted, broadly 

 expanded and reflexed and completely free throughout. 



Length 38, diam. 12, longest axis of aperture 14 mill. 



Length 35-37^, diam. 13J>, longest axis of aperture 13-i mill. 



Brazil : Corcobado near Rio Janeiro, and Macahe (Paz). 



Hiilhnii* odontostonifi Sown.. Zoological Journal, i, p. 51), pi. 5, f. 

 3 (1*24). REEVE, Conch. Icon., pi. 38, f. 228 PKH., Monogr. ii, 

 p. 82 ; iii, 3(V7 ; iv, 435 ; vi, 75 ; Conchyl. Cab., p. 138, pi. 1(3, f. 1-3. 

 HIDALGO, Journ. de Conchy]. 1870, p. 51. Helix ndnntoxtonm 

 \Vi>oi>, Ind. Testae. Suppl., pi. 7, f. 28. Pupa odontosfoma GRAY, 

 Ann. of Philos., n. ser., ix, p. 413. DESHAVKS in Fer., Histoire, ii, 

 p. 204, pi. K)3, f. 1. Macrodontes odontoslomus Sovvb., W. (4. BIN- 

 NKV, Ann. N. Y. Acad. Sci., ii, p. 114, pi. 10, f. n (jaw and denti- 

 tion). Pupa erythrostoma MKNKK, Synopsis, edit. 2, p. 32, 1830 

 (new name for B. odontostmmt Sowb.). rtfttmilio gargnnlint DESH. 

 in Lam., An. s. Vert., viii, p. 214 Odontostoimis gargantula I>i;< K, 

 Index, p. 54. Macrodontes sowerbeyH SWAINS., Malacology, p. 334 

 (1840). 



The pink aperture is broader and shorter than in the other species 

 with a long, arcuate, basal keel, and it is less closed by the teeth. 



This species has been supposed to be the Helix garyantua of Fer- 

 ussac. but the original description, " Bouche armee de gros plis on 

 dents alongees . . . Coquille aussi rare que singuliere, de plus de 

 deux pouces de longueur," indicates that the original gargantua was 

 0. pantagruelinus. 



