4 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 66 



CHILINA OLDROYDAE, new species. 



Plate 1, figs. 1, 3, 8, 10. 



Shell elongate, acuminate, thin, translucent, consisting of about 

 seven whorls (apical whorl eroded). IVliorls slightly convex, body- 

 whorl somewhat constricted behind the outer lip; suture minutely 

 margined; surface with numerous axial striae and slight plicae of 

 growth, and obscurely spirally striated, the striae more prominent at 

 the lower part of the last whorl ; a number of fine incised spiral lines 

 and a few broken or continuous incised lines here and there over the 

 whole body whorl. Aperture ear-shaped, occupying about half the 

 length of the shell, its outer lip thin and slightly sinuous. Columella 

 broadly flattened, slightly excavated, its edges somewhat arcuate, and 

 bearing at its upper inner end a prominent oblique fold. Color, pale 

 yellowish olive; body whorl with a band of arrow-head markings 

 of chestnut near the suture, a similar band encircling the base, and 

 two faint broad bands on the middle portion of the whorl. On the 

 penultimate whorl all the bands are concealed by the body whorl, 

 except one band of arrow-head markings near the middle of the 

 whorl. Earlier whorls pale. Columella and parietal callus white, 

 interior of shell whitish tending to livid flesh color. 



The type. Cat. No. 359906, U.S.N.M., measures : length, 42 mm. ; 

 diameter, 19 mm. ; length of aperture, 22.5 mm. It comes from Lake 

 Fetalafquen, in the Andes, in the northwestern part of the Province 

 of Chubut, Argentina, and was received from Mrs. T. S. Oldroyd. 



In a general way this shell in form and size recalls the well-known 

 Lymnaea stagnalis Linnaeus. Its nearest relatives are Chilina 

 fulguTata hatcheri Pilsbry and C. smithi Pilsbry. Its size and 

 locality at once separate it from the former, while its thin texture, 

 color, and locality distinguish it from the latter. 



Like C. smithi, this species varies much in form and size. Its 

 coloration in the eight specimens at hand is fairly uniform except in 

 the varying intensity of the color bands. Five of the specimens are 

 more chunky (for example one has a length of 30 mm. and a diam- 

 eter of 161/2 mm.). All the color bands on these show a more or less 

 strongly marked tendency to have all four of the color bands made 

 up of arrowheads. One specimen, typical in form, has the whole 

 surface covered with zigzag lines of reddish, with accentuated arrow- 

 head spots to form the four color bands. One specimen is so dis- 

 tinctly shouldered that it is turrited. 



CHILINA OLIVACEA. new species. 



Plate 1, fig. 9. 



Shell ovoid, moderately solid, smooth, unctuous, distinctly slopingly 

 shouldered, upper whorls angulated, sutures distinctly margined, 



