274 PROCEEDINGS OF THE ACADEMY OF 



brj^onic whorls in the least worn shells ; broadly two-banded with chest- 

 nut, blackish in places, the upper band sometimes extending to the 

 suture. 



Alt. 9 8.7 10 mm. 



Diam. 15.2 15 15 " 



3. Limestone Mountain, Huachucas, south side at 8,000 feet eleva- 

 tion (PI. XXIV, figs. 29-31). The shells are whitish with some fleshy 

 or livid streaks or dots, and with two bands, or clouded and suffused 

 with purple-brown. Similar to typical concentrata except that the 

 umbilicus is decidedly smaller within. The last whorl descends to the 

 aperture. They arc like 0. s. huachucana, No. 3, from Brown Canyon, 

 in miniature. They are rounded or slightly angular in front. The 

 sculpture is suhobsolete, without a trace of spirals. 



Scalariform monsters are not rare, but the inception of that abnormal 

 condition seems to be invariably traceable to an injury of the shell. 

 One such is figured (PI. XXIV, fig. 31). 



4. Limestone Mountain, south side, 8,000 feet. Like the preceding, 

 but more elevated and fleshy white with pinkish apex. The last whorl 

 descends rather deeply (PI. XXIV, fig. 32). 



Alt. 10 9.7 8.7 mm. 



Diam. 15.3 15.5 13.7 " 



5. Limestone Mountain, north side, 8,000 feet. Similar to the two 

 preceding lots in size and sculptm-e, but broadly two-banded with 

 purple-black, or entirely of this color (PL XXIV, figs. 25, 26, 27). 

 This lot resembles 0. s. hunchucnna, Nos. 11, 12, from Carr Canyon, 

 which are also from a high altitude. No. 5 from 7,000 feet. Brown 

 Canyon, has also similar coloring, but is much larger. 



This lot, like all seen from Limestone Mountain, does not have the 

 umbilicus so wide within as in typical concentrata. 



Alt. 9 8.8 9.3 mm. 



Diam. 16.3 15.5 15.2 " 



6. The series of five specimens sent by Dall as 0. s. concentrata from 

 Hacheta Grande Mountain, Grant coimty. New Mexico, one of which is 

 figured on PI. XXV, fig. 60, shows no appreciable divergence from the 



