236 NILS HJ. ODHNER 



whorls; the variation of shape thus being considerable. — Centinela Ridge, 

 about 500 m, on ferns and under leaves, a few sps., max. h. 6,3, and about 

 350 m, thick forest, a few sps., max. h. 5,5. —  The Yunque quebrada, lower 

 part, 6 shs., max. h. 7,3, wh. 8. — Puerto Ingles, about 400 m, thick forest, many 

 sps., max. h. 6,4, and about 200 m, among leaves, some small sps. — Rabanal, 

 about 400 m, under leaves, a few sps., max. h. 5,5, about 300 m, many sps., 

 max. h. 6,5, and in the quebrada, under leaves, many sps., max. h. 6. — Below 

 Damajuana, about 300 m, under leaves, some sps., max. h. 6,8, and in thick 

 forest, many sps., max. h. 8.. — The Portezuelo quebrada, to 200 m, on ferns 

 and under leaves, many sps., max. h. 4,8. 



Variations: T. bilamellata varies in proportions, as shown by the measure- 

 ments given; normally it is rather wide, sometimes, however, strikingly slender. 

 In the latter case also, the dentition of the aperture is subject to increase, 

 inasmuch as there are three palatal folds or teeth, sometimes united by a 

 vertical callus existing occasionally also in the typical form. In the last-named 

 variety the columellar fold is flanked with a distinct tooth below and an obsolete 

 one above. This variety is shown on plate 9, fig. 36. That these forms are 

 merely varieties of the same species is proved by the fact that there exist 

 transition specimens and, further, that the young specimens, still contained in 

 the uterus of the mother, show differences in shape and dentition even within 

 the same mother (cf. fig. 18 a — d). In young specimens of the three-toothed 

 variety the teeth appear in their strong performation sooner than in young ones 

 of forma typica. This variety also differs from the latter in its smoother and 

 more glossy surface, as well as in its reddish-brown colour, whereas the type 

 is more coarsely striated by growth lines and has a horn-green hue. All forms 

 very often have an encircling Hght band on the middle of the last whorl, often 

 accompanied or substituted by a dark-brown one. The young individuals of 

 forma typica are distinctly angled in the basal periphery, though not to the same 

 degree as in T. conica. 



The three-toothed variety is present from the following localities: Centinela 

 Ridge, about 650 m, under ferns, 5 sps., max. h. 5,4, whorls 7, and 500 m, on 

 ferns and under leaves, 4 sps., h. 4,7. — Salsipuedes Ridge, about 350 m, many 

 sps., max. h. 4,5. — Puerto Ingles, about 400 m, some sps., max. h. 6. — Puerto 

 Frances, about 400 m, i sp., h. 5. — Piedra Agujeriada Valley, many small sps. 

 — Below Damajuana, about 300 m, i sh., h. 4,5. 



Tornatellina conica Anton. PI. 9, fig. 37. — Masatierra, Aug. 1917: 

 Centinela Ridge, about 500 m above sea, under ferns, numerous sps., max. h, 5,2, 

 and about 350 m, thick forest, some sps., max. h. 5. — Puerto Ingles, about 

 400 m, thick forest, .some sps., max. h. 6,4, wh. 11, and 200 m, among leaves, 

 2 small sps. — Piedra Agujeriada Valley, some small shs. — Rabanal, 

 down in the quebrada, under leaves, many sps., max. h. 5,6, wh. 10, and about 

 300 m, many sps., max. h. 4,5, br. 3, another sp. h. 4,7, br. 2,6, thus varying 

 in proportions; about 400 m, under leaves, 4 small sps. — Below Damajuana, 

 thick forest, under leaves, about 300 m, 4 shs., max. h. 5,2. — The Porte- 

 zuelo quebrada, to 200 m, among leaves and on ferns, some shs., max. h. 

 4,8. — Salsipuedes Ridge, about 350 m, on ferns and under leaves, 3 sps., max. 



