76 THE NAUTILUS. 



shell dark livid olive, often lighter near the aperture with a broad 

 band near the suture and numerous, narrow revolving bands below, 

 of a paler olive; near the base there is usually an area somewhat 

 darker ; throat deep livid purple, with a light subsutural band, and 

 the smaller bauds visible by transmitted light, the peristome bor- 

 dered with a conspicuous vitreous red margin, especially on the 

 inner lip ; aperture rounded above and below, with a thick parietal 

 callus, umbilicus narrow and deep. Alt. of shell 60, of last whorl 

 58, of aperture 47 ; lat. of shell 65, of aperture 35 mm. Operculum 

 thin, horny, externally finely concentrically striated, and of a black- 

 ish olive-green. 



Habitat: Homosassa River, Florida, collected by Mr. George 

 Pine. 



This species is related to A. depressa Say and A. Ghiesbrechti Phil., 

 but separated from both by its form, sculpture and color. It is most 

 readily recognized by its deep red border to the aperture, wide shell 

 and very depressed spire. 



NEW POLYGYRAS FROM WHITE MOUNTAIN, NEW MEXICO. 



BY T. D. A. COCKERELL. 



Polygyra altissima n. sp. 



Shell with 5J whorls, pale yellowish-brown, suture moderately 

 deep, spire flattened and low, periphery rounded ; apical whorls 

 nearly smooth, with little sculpture as far as the middle of the 

 penultimate whorl, after which the shell becomes distinctly and 

 strongly obliquely ribbed, the ribs near the aperture being particu- 

 larly strong ; the last whorl bears about 48 of these ribs. Umbili- 

 cus narrow and deep. Aperture obliquely semilunar ; the peristome 

 subcircular except where interrupted by the parietal wall, strongly 

 thickened, recurved with a sharp edge, yellowish- white, without 

 teeth. No parietal denticle. Diam., max. 12, min. 10 mm. ; alt. 6 mnr. 



Hab. Highest summit of White Mountain (Sierra Blanca), 

 Lincoln Co., New Mexico, altitude 11,092 feet; three under a rock, 

 Aug. 14, 1898. Collected by Prof. C. H. T. Townsend. 



The specimens are practically alike, and differ greatly from P. 

 rhyssa Dall, to which they are most nearly related, and from which 

 they are presumably descended or ascended, I suppose we should 

 say, considering the altitude at which they are found ! 



