218 INVERTEBRATA OF MASSACHUSETTS. 



Limn^'a umbilicata. 



Shell small^ ovate ; whorls Jive, rounded, and marked mth fine 

 decussating lines ; suture deeply impressed ; aperture small, oval ; 

 no conspicuous fold on the columella ; umbilicus distinct. 



Figure 149. 



State Coll., No. 136. Soc. Cab., No. 2402. 



Limnaj^a umbilicata, Adams ; Bost. Journ. JVat. Hist., iii. 325, pi. 3, f. 14. Silli- 

 mans Journ., xxxix. 374. 



Shell small, short-ovate, apex obtuse ; whorls five ; very con- 

 vex and rounded, slightly oblique, their surface reticulated with 

 fine lines, and modified by numerous facets or indentations, ar- 

 ranged in imperfect revolving series, four or five in number ; su- 

 ture deeply impressed ; aperture small, about half the length of 

 the shell, broad-oval, not expanded but rather seeming contracted ; 

 outer lip sharp, thickened within by a sub-marginal, pinkish-color- 

 ed deposit ; passing backwards on the inner side in a smooth and 

 rounded plate, it joins the preceding whorl at about half the height 

 of the aperture ; a thin glazing of enamel covers the remainder of 

 the inner margin. There is scarcely any approach to a fold on 

 the pillar ; umbilicus large and deep. Length -^^ inch, breadth 

 i inch, divergence 65°. 



First collected by Mr. Shiverick, at New Bedford. 



Limnda modicellus is of about the same size and general appearance ; 

 but its surface is smooth, its whorls more oblique, its mouth twice as 

 large, and it has no conspicuous umbilicus. L. caperata is similar in 

 its form, and its small, oval aperture, but is at once I'ecognised by the 

 regular revolving, hispid lines. 



LiMNiEA MODICe'lLUS. 



Shell ovate, thin, light-olive colored ; lohorls four, convex ; su- 

 ture deep ; aperture rather large, ovate ; fold of columella conspic- 

 uous ; sub-umbilicated. 



Figure 151. 



State Coll., No. 71. Soc. Cab., No. 2403. 



Lymncus modicellus, Say ; Jojirn. /lead. jXat. Sc, v. 122. 



