42 COLIMACEA. 



Conch., p. 39> pi- 18, f. 32; Clausilia rugosa, var., Alder, 1. c, 

 p. 32 ; Clausilia similis, Gilbertson, MSS. 



Shell dark umber-brown, ventricose; body long; spire small, 

 consisting of from nine to eleven rather inflated volutions ; 

 covered with pretty strong, elevated, somewhat granular striae, 

 iu consequence of a few spiral ridges on the lower volutions ; 

 aperture oblong-ovate, contracted above, and a little rounded 

 below; lips white, rather narrow; columella with two plaits, the 

 superior one placed near the upper portion of the aperture and , 

 pointing downwards, the lower one near the under side, inter- 

 nally bifurcate, and pointing upwards. Size, about five-eighths 

 of an inch long, and one-eighth in diameter. 



It is known from Clausilia rugosa by being longer, and 

 more ventricose. 



Found in the North of England, under moss in rocky situa- 

 tions. 



Genus XVIII—PUPA.— Lamarck. 



Shell oblong, cyhndrical, thick ; spire with numerous volu- 

 tions, terminating in an obtuse apex ; aperture elhptical for the 

 most part, sometimes a little square at the upper extremity, 

 and rounded anteriorly ; peretreme and inner lip continuous, 

 slightly thickened, and reflected ; upper part of the aperture 

 frequently provided with a single tooth within : many of the 

 species furnished with longitudinal ribs. 



The young shells of the genus Pupa are trochiform, with a 

 simple cavity at the base. Mr. Alder first pointed out a 

 remarkable structure in the interior of Pupa umhilicata and 

 P. Anglica. This consists of a raised thread-like laminar 

 process winding spirally round the columella, and a similar 

 lamina running spirally on the upper side of the volutions, with 

 a series of small, flat, nearly transverse, testaceous plaits, situate 

 at intervals, in the interior of the volutions. These are some- 

 what analagous to the septa in the genus Segmentina. These 

 plaits are not, however, continued through the lower volutions. 

 Their use has not yet been ascertained. 



1. Pupa muscorum, pi. V, f. 1. 



Pupa muscorum, Drapernaud, Hist, des Moll., p. 59, var. a; 

 Pfeiffer, I, p. 57, pi- 3, f. 17, 18; Pupa delucida, Rossmassler, 



