THE NAUTILUS. 127 



pyramid in others, and is considerably lunger than the aperture ; tlie 

 aperture is roundly elliptical and almost continuous, differing mark- 

 edly in this respect from kumilis ; the inner lip is more erect in the 

 present species, which causes the umbilicus to be round, deep and 

 open. The umbilical region is gracefully rounded. Typical ex- 

 amples measure as follows : 



Length 6.00; width 3.00; aperture length 3.00; width 1.7.1 mill. 

 (Indiana.) 



Length 6.00; width 3.00; aperture length 2.50; width 1.25 mill. 

 (Penn.) 



Length 5.50; width 3.00; aperture length 2.75; width 1.50 mill. 

 (Ills.) 



This species is widely distributed, being found from Maine to Cali- 

 fornia and from Canada to Mexico. 



Lymncp.a desidiosa Say var. modicella Say. 



Lymseus modicellus Say, Jour. Phil. Acad., V, p. 122, 1825. 



Say described this species from two specimens which are still pre- 

 served in the Philadelphia Academy. It would seem to be distinct 

 enough to be recognized at least as a variety of desidiosa, to which 

 it is more closely allied than to Int mills. The principle characteris- 

 tics are the short, dome-shaped spire, the regular elongate-ovate aper- 

 ture and the large size of the last whorl as compared with the spire. 

 The umbilical chink is narrowly open and there is a small plait on 

 the columella. Typical specimens measure as follows: 



Length 8.50; width 4.75; aperture length 4.75; width 2.75 mill. 

 (Say's type.) 



Length 7.75; width 3.25; aperture length 4.50; width 2.25 mill. 

 (Berry Lake.) 



Length 7.00; width 3.50; aperture length 4.50; width 2.00 mill. 

 (Berry Lake.) 



The range of this form, as far as known, is from Ontario to Oregon 

 and south to Texas. It has been found in Big Payette Lake, Idaho, 

 at an altitude of 5,000 feet above the sea level. 



The forms described by Dr. Lea as L. plica, planulata, exigua and 

 ruslica seem to be absolute synonyms of desidiosa, some of these 

 being, in all probability, immature forms. The types of exigua and 

 ruslica are not in existence, so far as known. They are not in the 

 Philadelphia Academy nor in the Smithsonian Institution. 



