THE NAUTILUS. 53 



small example of that species. Besides its small size it differs from 

 that species in having the sutures more impressed, the aperlnre 

 longer, the spire slenderer and the whorls more shouldered. It 

 seems to be quite distinct and easily recognized. 



There is some variation in the length of the spire, many specimens 

 having a rather long spire while in others the spire is much depressed 

 and the whorls humped, this last being in abnormal forms. 



This species was at first thought to be a new one, but after careful 

 study it seems to agree very well with Lea's description of parva and 

 with specimens so named by him in the Smithsonian Institution. In 

 his remarks under parva he says, \ l This is the smallest species which 

 has come under my notice. In general form it resembles L. curta, 

 herein described. It is rather less inflated, has a longer aperture, 

 and is diminutive. The perforation, too, is smaller and the colu- 

 mella more curved. 



In a paper entitled " Critical Notes on the Smaller Lymnaeas," in 

 the March Nautilus, the writer made this species a synonym of 

 curta, but a study of the material from Lake James, which is unusu- 

 ally abundant, would make it seem to be a w r ell-recognized species. 

 Specimens were submitted to the writer by Dr. Sterki, Mr. Bryant 

 Walker and Mr. L. E. Daniels, the latter gentleman having col- 

 lected them. 



Parva would seem to be a common species, and will probably be 

 found in many cabinets under the all-embracing name of " humilis." 



VERTIGO PERRYI, N. SP. 



BY V. STERKI. 



Shell minute, dextrorse, ovate with the apex rather acute, rimate; 

 thin, transparent, of rather dark brown color with a slight greenish 

 tinge; whorls 4^ rather rapidly increasing, separated by a moderately 

 deep suture, the last comparatively large, occupying over one-half of 

 altitude, rounded ; with a slight impression over the palatal fold ; 

 aperture well rounded, truncate, the margins slightly everted, I lie 

 outer margin barely impressed at the auricle which is marked by a 

 slight angle projecting over the level of the peristome ; no callus in 

 the palate ; lamellae and folds three or four, small, very short, of 

 brownish color ; the parietal, columellar and inferior palatal, and 



