78 CAUCASIAN LAURLE. 



pressed, erect behind, arising from the base of the outer mar- 

 gin ; a long crest-like tooth in the middle of the right margin, 

 2 or 3 other minute fold-like, obsolete teeth in the basal mar- 

 gin. Length 5, diam. 2.5 mm. (Mouss.). 



Transcaucasia: Lailaseh, prov. Kutais (Mousson) ; Bor- 

 schom, drift of the Kura at Michailowe, living at Kutais. 

 Nakerala Mts., Imeretia (Leder), a small form. Suram Mts. 



Pupa superstructa Mousson, Journ. de Conchyl., xxiv, 

 1876, p. 37, pi. 2, f. 7.— Boettger, Jahrb. D. m. Ges., vi, 1879, 

 pp. 30, 404; vii, 1880, p. 138; viii, 1881, p. 229; x, 1883, p. 

 180, with var. lederi, pi. 7, f. 3; var. zonata, pi. 7, f. 2. — 

 Charadrobia superstructa (Mouss.) var. unibamlis Boettger, 

 Jahrb. D. m. Ges., xiii, 1886, p. 149, pi. 3, f. 5a-b. 



A widely-spread Caucasian form, well distinguished by the 

 thick, basally crenulate callus of the lip, the emerging colu- 

 mellar lamella, a short one above, the well-developed though 

 short twin lamella connected with the angular lamella at its 

 right base, and the short, directly entering upper-palatal fold. 

 The surface has low traces, more or less obsolete, of rather 

 coarse riblets; behind the well-expanded lip these are gener- 

 ally stronger. Length 4.7, diam. 2.4 mm., iy 2 whorls. Mt. 

 Suram. 



A small form of the typical superstructa was found by Mr. 

 Hans Leder in the Nakerala Mts., Imeretia. It differs from 

 those of the region of Kutais only by the smaller size, recall- 

 ing var. zonata, but it does not vary from the type in shape, 

 form of the aperture or denticulation. Length 4^4, diam 

 nearly 2 ^ mm. (Boettger). 



At Borschom (Leder, 1886) there is not rarely the trace of 

 a dark band on the last whorl, the specimens otherwise typical. 



Young shells of superstructa, Dr. Boettger (1879) writes, 

 differ from those of cylindracea, aside from the shape, only 

 by the longer internal radial welts, extending over nearly the 

 whole breadth of the base, which are arranged like the spokes 

 of a wheel, and closer together (so that there would be places 

 for about 6 on the last whorl, though only the usual 3 or 4 

 are present) than in cylindracea, with which the lamella? of 

 youth otherwise agree in structure. 



