NEW SNAILS—PARODIZ 441 
the forms mentioned from Corumb4, Matto Grosso. When these points 
are settled, we can distinguish the following fine subspecific forms. 
Drymaeus poecilus poecilus (d’Orbigny) 
This is the form which d’Orbigny himself called major (Voyage dans 
VAmerique méridionale . . ., vol. 9 (Atlas Zool.), Moll. pl. 31, figs. 
7 and 8, 1836; Reeve’s Conchologia iconica, vol. 5, Bulimus, f. 91, 
1848), but inasmuch as d’Orbigny referred to it as the first, most 
abundant and typical form, there is no reason to maintain such a 
subspecific name; this is indeed the typical form because it has the 
principal features of the Latin and French descriptions and because 
its range is southward from the foothills of Bolivia to the Argentine 
province of Catamarca?, about 1,000 miles southwest of Corumbé 
(where it is not found but is replaced by other subspecies). Posi- 
tively poecilus poecilus is not living in Peru, Matto Grosso, or even 
eastern Bolivia; its distribution in Argentina includes the provinces 
of Salta, Jujuy, Formosa, Tucum4n, Catamarca, and Santiago del 
Estero; the other forms are absent from that area. This separation 
prevents in greater part any interbreeding; thus the characters are 
more permanent, and the typical form represents a well-limited 
subspecies. This limitation does not apply with the other varieties, 
because at CorumbA several races are living together. Perhaps, in its 
extreme northern limit, poecilus poecilus makes contact with some 
supposed varieties from Peru (the many Dall ‘‘mutations’’) and some 
interbreeding may occur, but in the rest of the area it remains as a 
pure stock. This fact, very simple, was often missed, because the 
earlier writers used mostly northern or eastern materials rather than 
those from the Bolivia-Argentina border. 
Drymaeus poecilus minor (d’Orbigny) 
Drymaeus poecilus minor, Parodiz, Nautilus, vol. 71, p. 25, 1957. 
PLATE 2, FraurE 10 
This form is distributed on the low plains of Bolivia from the 
foothills to the eastern region of the upper Paraguay River and makes 
contact at Corumb4 with other forms; some specimens show a slight 
relationship with these forms, but the subject form, especially from 
the western side of the plains, can be readily identified with d’Orbigny’s 
(1836) figure 6. 
The form has no dark subsutural spiral band, except rarely one 
broken up into spots, and many specimens from CorumbaA accord with 
the author’s description. The other variations included by d’Orbigny 
are localized in different forms as we shall see later. Also under 
minor were included specimens of another species, D. lynchi Parodiz 
(which is d’Orbigny’s fig. 10); however, poecilus never has axial 
2 Doering (1879) said that Brackebusch and Hieronymus collected the species very abundantly in Cata- 
marca, but according to our records itis more abundantin Tucum4n. 
