424 A MANUAL OF AMERICAN LAND SHELLS. 



very small side cusps ; all the cusps bear distinct cutting points. The 

 lateral teeth are very much larger than the centrals. The base of 

 attachment is about as high as wide, its inner lower lateral expansion 

 suppressed as usual. The upper edge is squarely reflected. The 

 reflection is very large, and bears one stout median cusp, extending 

 almost to the lower edge of the base of attachment ; there is also an 

 outer, much smaller side cusp, and a less developed, sometimes subob- 

 solcte inner side cusp; all the cusps have distinct cntting points, pro- 

 ])ortioned to their size, that on the central cusp being greatly devel- 

 oped. In S. (lecollata (Terr. Moll., V, Plate IV, Fig. Q) the inner 

 cutting point is also much developed and joined to the central cutting 

 point. The marginal teeth in S. decollata {b) are but a modification of 

 the laterals, with the suppression of the inner cusp and cutting point; 

 the extreme marginals (c) differ in the greater development of the 

 reflected portion and equalization with it of the cutting points, of which 

 there are but two (see also below). In S. suhula (Terr, Moll., V, Plate 

 IV, Fig. P) the marginal teeth (b) have more numerous cutting points, 

 formed by the bifurcation of tlie inner and outer cutting points. The 

 second denticle from the inner side is the largest (see Fig. 470). It will 

 be noticed that in 8. decollata both the side cutting points of the laterals 

 are quite thorn-shaped. 



Subgenus EUMINA, Risso. 



Animal heliciform, blunt before, pointed behind ; mantle posterior, 

 thin, protected by a shell ; respiratory and anal orifices on the right 



of tlie mantle, under the peristome of the 



^^ shell; generative orifice behind the right 



.t--^^**^ eye-peduncle; no locomotive disk ; no cau- 



Aiiinnl ot Stinurji/ia decollata. ^hll mUCUS porC. 



Shell obsoletely rimate, calcareous, normally truncated, cylindrically 

 elongate ; remaining whorls 4-G, the upper truncated ones 8-10, the 

 upper one globular; aperture semi-oval ; peristome straight, thickened 

 within, its margins connected with callus, the columella twice as short 

 as the external one ; columella not truncated. 



Jaw and lingual membrane: see p. 458. 



A single species is known, which inhabits Europe. It has been in- 

 troduced by commerce into Charleston, S. C. (See below, p. 456.) 



