PILSBRY: non-marine MOLLUSCA of PATAGONIA. 537 



Chilina fulgurata sp. nov. 



(Plates XLIII, Figs. 11-15 ; XLIIIrt, Fig. 4.) 



The shell is imperforate, elliptical, with short, conic spire, thin. Fully 

 grown shells are in large part dull gray from loss of the cuticle on the 

 back, but what remains in front is dull pale yellowish, with numerous 

 dusky brown, angular streaks (fig. 15). Younger shells (fig. 1 1, length 12 

 mm., and fig. 12, length 13.2 mm.) are densely marked with reddish-chest- 

 nut, zigzag stripes on a whitish or in places yellow ground, the penultimate 

 whorl with a blue ground. In an older stage (figs. 13, 14, length 16 mm.) 

 the ground color on the back and spire is blue, but whitish at the base. 

 The brown stripes have four forwardly projecting angles. The apices are 

 more or less eroded in the type lot, but there are evidently not less than 

 5 whorls. The aperture shows the external marking on a ground more 

 or less suffused with rich light chestnut in shells not fully adult, but in 

 old shells the markings are not seen, and the throat becomes chestnut, 

 fading to whitish near the lip. The columella is rather narrow, white, 

 straight, or only slightly arcuate, and bears a small and rather thin, very 

 oblique lamella above. ^ 



Fig. 15. Length 19, diam. 10.7, length of aperture 12.9 mm. 

 " 13-14. " 16, " 8.9, " " 10.9 " 



Small stream on the Rio Chico, 5 miles above the Sierra Oveja, type 

 locality ; also northw^ard to the foothills of the Andes, in various springs 

 and streams. 



This species has the elaborate color-pattern of Chilina puelcha 

 d'Orbigny, but differs from that by its comparatively narrow contour. The 

 dimensions of the type of C. puelcha are, length 20, diam. 15 mm. C. 

 fulgurata is probably related more closely to C. parchappii d'Orb., a 

 more slender and lengthened species, deficient in color-ornamentation. 



The type of C. fulgurata is drawn in Plate XLIII, figs. 13, 14, and 

 Plate XLIIL?, fig. 4. 



In springs twenty-five miles above the Sierra Oveja, a large, thin form 

 of fulgurata was found. The elaborate color-pattern persists through 

 the period of maturity, but fails in the aged or gerontic stage. The sur- 

 face has minute axial plicae and distinct spiral lines, giving it a decussate- 



' This lamella, while correct as to outline in figures 13 and 15, is represented as more massive 

 than it really is. 



