28 MOLLUSCA. 
less green, more inflated in its form, and with a shorter aperture, and 
smaller body whorl than the latter. It has the size, but not the colour 
or columella of S. manuana. 
Figure 20, aperture, and 20 a, profile of the shell, magnified; 20 4, 
natural size. 
SUCCINEA RUSTICANA (Gould). 
Testa-elongata, ovato-conica, tenuis, pallid? virens, impolita, lineis incre- 
mentalibus inequalibus et crassis striata, subtus convexa: spira acuta, 
anfractibus tribus convexiusculis: apertura ovata, quadrantes tres 
longitudinis adequans ; columella arcuata, perspicué plicata. 
Succinea rusticana, Goutp; Proceed. Boston Soc. Nat. Hist., ii. 
187. Dec. 1846. Expedition Shells, 31. Prreirrer; Monog. i. 523. 
SHELL elongate, ovate-conical, rather large, thin, and fragile; pale 
greenish horn-colour, surface rude and without lustre, coarsely and 
irregularly marked by the lines of growth. Spire acute, of three or 
more moderately convex whorls, separated by a well-impressed suture, 
the last whorl large and long, narrowing towards the base; body por- 
tion of the face of the shell moderately large. Aperture ovate, three- 
fourths the length of the shell ; fold of the columella distinct. 
Length of axis half an inch; breadth one-fourth of an inch. 
Inhabits Oregon. 
Somewhat related to S. pudorina, in form, but very different in 
colour. 
Figure 29, front of the shell; 29 a, side of the shell, with the animal ; 
29 6, profile of the shell. 
Succinea crocata (Gould). 
Testa pinguts, sub-solida, sub-opaca, ovato-globosa, saturate crocea, liners 
