12 BULIMULUS-SCUTALUS. 



sents an obese specimen, while those of PfeifFer and Gay are more 

 normal, but both stout and slender specimens are represented in one 

 of the trays before me. 



Subgenus SCUTALUS Albers, 1850. 



Scutalus ALBERS, Die Hel., 1850, p. 160. ALB.-MART., Die Hel. 

 1860, p. 217, type B. proteus. 



Ovate-conic, mostly perforate or umbilicate Bulimuli, with the 

 nepionic whorls striolate or densely pitted, aperture ovate with the 

 lip often expanded or thickened ; columella not distinctly folded, its 

 edge dilated and reflexed. Type B. proteus. 



A group of rather solid species, mainly developed upon the Andean 

 plateau of Ecuador, Peru and Bolivia, but extending to the south 

 as far as north-western Argentina. It is essentially an Andean 

 type, the allied section Plectostylus replacing it in Chili and the 

 typical Bulimulus and Leptomerus occupying the regions to the east- 

 ward and north-east. 



I do not know of any terrestrial snails living at greater altitudes 

 than some of the members of this subgeuus. B. culmineus, a species of 

 the Bolivian and Peruvian Andes in the neighborhood of Lake Titi- 

 caca, ascends to 5,000 meters (over 16,500 ft.) above sea level. B. 

 anthisanensis, an Ecuador snail, lives at 4,200 meters (14,000 ft.) ; 

 and B. caliginosus and a few other forms from the same region, have 

 been found at an equal height. 



Scutalus as here understood differs widely in limits from the 

 assemblage of species grouped under the same name in Die Heliceen 

 and Nomenclator Heliceorum. The recognition of sculptural char- 

 acters of the nepionic stage as diagnostic of subgeneric groups, 

 necessitates the removal of species with smooth and those with costel- 

 late apices, which were formerly included in Scutalus. By this 

 elimination, the group becomes restricted geographically to a defi- 

 nitely limited though extensive region wherein like physical condi- 

 tions prevail. Scutalus in its former limits included species diverse 

 in characters of the antenatal shell, distributed over all of western 

 and northern South America, Mexico and the southern United 

 States, in regions more or less like physically, but widely differ- 

 ent in most of their faunal factors. 



Group of B. proteus. 



This is the west Peru type of Scutalus, characterized by the 

 more or less strongly granose surface, frequently banded and much 



