90 THK NAUTILUS. 



A NEW CALIFORNIAN VERTIGO. 



BY V. STERKI. 



Vertigo occidentalis, n. sp. Plate XI, fig. 2. 



Shell of the shape, size and appearance of a smaller Vert, ovata 

 Say, but perforated ; short ovate, chestnut colored, transparent ; 

 slight impressions over the palatal folds, no crest, no callus inside ; 

 lamellae and folds : parietal and angular close together, coherent, 

 short, low, somewhat massive ; columellar only indicated by a slight, 

 angular projection ; the two palatals quite small, short, the upper 

 closer to the margin. Alt. 2 mill. Soft parts not seen. 



Habitat : San Bernardino Mts., California, at alt. 7600 feet, col- 

 lected in the summer of 1907, by Mr. S. S. Berry, one specimen. 



It is rather inopportune to establish a species on a single speci- 

 men. But the one seen is mature, with no trace of a deformity, and 

 with all its external resemblance to V- ovata, is evidently distinct. 

 It has been carefully compared with many ovata from New Mexico, 

 Arizona, California e. g., the Cuyamaca Mts. near San Diego, to 

 Montana and Washington, etc. None of them was perforated, and the 

 lamellae and folds of occidentalis are different as to size, shape and 

 location from those of ovata, even in immature specimens. It has 

 been pointed out, years ago, that their location and shape are of 

 more consequence than their mere presence or absence, at least in 

 some forms. 



NOTES. 



Specimens of Planorbis magnificus Pilsbry have been kept alive in 

 small aquaria at the National Museum for more than a year. Those 

 which were adult when collected in 1906 (October) are all dead, 

 apparently from old age, but before dying they left progeny now 

 about six months old and one-third grown. It is therefore probable 

 that the life of the species is about two years in length. The young 

 have well-pigmented eyes, in the usual situation, but in the adult 

 these have so degenerated that no trace of pigment or lens is visible 

 in the living animal by transmitted light. Their favorite food is 

 lily-pads, which they devour with great rapidity and on the lower 

 surface of which they are most likely to be found.- -W. H. Daul. 



