344 MEXICAN BO UNDARY SHELLS— BALL. 



toward the umbilicus; basal part of tlie peristome Avith two distinct, 

 clear-cut lamella' transverse to the lip; outer lij) broader than the rest, 

 receding, with a similar lamella set on somewhat oblicjuely and more 

 deeply within the aperture. Height of shell 5.5, maximum diameter 

 13, minimum diameter 11 mm. 



Huachuca Mountains, Arizona, and Hachita Grande Mountain, Grant 

 County, Xew jNIexico, Dr. 3Iearns, at an altitude of 8,000 to 9,400 feet. 

 No. 130012, U.S.N.M. 



No living specimens were collected, but tlie number of dead ones 

 indicates that the species is not uncommon where I'ound. This species 

 is instantly distinguishable from any of the other species of rolyfiyra 

 which i)ossess a A-shaped parietal lamella by the presence of three 

 distinct, Avell defined teeth on the outer lip. All the other forms have 

 two, or two with an obscure undeveloi)ed flattening in addition. These 

 teeth closely resemble those of Polygyra levettci, and if that species had 

 two parietal laraelltTB and was more depressed, it would difter from 

 P. mearnsii chiefly by its greater size and number of whorls. P. nuutnisii 

 therefore forms a connecting link between those forms which have 

 been called Dwdalocheila and Triodopsis. 



Family PUPID^. 



Genus HOLOSPIRA, Martens. 



This genus was separated from Cylindrellahj Albers' under the name 

 of Acera, Avhich had already 1)oen used in zoology and for which Von 

 Martens in his new edition of Albers's work^ substituted Holosjnra and 

 named H. jnlocerei, Pfeififer, as the type. The following is a free trans- 

 lation of the diagnosis of Albers: 



"Shell with an umbilical chink, turreted or spindle-shaped, with a 

 conical not truncate apex; 11 to 14 whorls of which the last is little or 

 not at all protracted; basecarinate; columella plicate; aperture (piad- 

 rangular; peristome free, expanded." 



Holosloma piloccrei appears to be a rare shell; at least I have not 

 been able to examine a specimen, though many so named, but which 

 proved different, have come under inspection. The figures of this spe- 

 cies are somewhat discrepant as already noted by Crosse and Fischer,^ 

 and may represent more than one species, since the internal structure 

 was not examined by Pfeiffer and the external characters, beside being 

 somewhat variable, are very similar in the different species. ITowever, 

 three of the original Pfeifferian specimens were examined by Strebel 

 and Pfeffer* who describe the internal characters. It has a idait on 

 the j)illar and, near the end of the penultimate whorl, three other 



'Helif-eeu, \>. 209, 1850. 



2 Page 39, 1860. 



='Moll. Terr, et Fhiviat. «le Mexique, T, p. 330. 



■•Beitr. ziir Kenut. «ler Fauua Mex., p. 82, 1880. 



