1905.] NATURAL SCIENCES OF PHILADELPHIA. 245 



behind the lip there are fine, sharp strise. The embryonic whorl is 

 glassy, with fine radial strige on the outer side of the suture ; some part or 

 parts of the third or fourth whorls are sculptured with very minute raised 

 points in quincuncial order. The spire is low conic-convex, very obtuse 

 above, the first two whorls being almost in a plane. Whorls 6^ to 6f , 

 very narrow, and very slowly increasing; the first three are convex, those 

 following being decidedly flattened, onlj^ slightly convex. The last whorl 

 is acutely angular at the periphery, the angle more obtuse on its last 

 third. The base is convex. The suture descends a little to the aper- 

 ture. The lip is preceded by a creamy stripe, and the base is deeply 

 guttered behind the expansion. The aperture is very oblique, narrow 

 and lunate, obstructed by four teeth : a more or less sinuous, oblique 

 parietal lamella, two compressed, entering teeth on the basal lip, of 

 which the out«r one is higher and more compressed, and an oblique, 

 square-topped tooth within the outer lip. The sinus or notch between 

 the two basal teeth is slightly wider than that between the outer basal and 

 the outer lip tooth. The umbilicus is about one-sixth the diameter 

 of the shell. 



Alt. 14.3, diam. 6.5 mm. 

 " 13.3, " 6.3 " 

 " 13.3, " 6.4 " 

 " 13, '' 6 '' 

 " 13, '' 6 " 



Two other specimens of the type lot measure 14 and 14.3 nun. 

 diameter respectively. 



Chiricahua Mountains, Arizona, in the South Fork of Cave Creek, 

 at the base of the mountain. Types No. 87,019, A. N. S. P., collected 

 by Mr. Ferriss, February, 1904. 



The young shells show the characteristic punctation better than 

 adults. At resting periods in the neanic stage of growth a callous rib 

 is formed within the lip. When this occurs early (as in the specimen 

 figured, PL XI, fig. 11, 8 mm. diameter) the rib is much thicker in 

 the naiddle. When it occurs in the last whorl it is more equally 

 thickened. 



This species is closely related by shell characters, but not by its soft 

 anatomy, to A. levettei angigyra of the Huachuca range, agreeing with 

 that form in the close convolution of the whorls, the angular periphery 

 and the general arrangement of the teeth. But all fresh specimens of 

 A. angulata show a quincuncial punctation of some part of the neanic 

 whorls, not present in the Huachuca form, and the two especially 

 differ in the shape of the whorls, the upper surface of which is flattened 



