8 Observations on the Terrestrial 



Pallifera. xov. gex. 



Buccal plate arcuate, rounded at sides ; having seven prominent ribs, which 

 crenulate its cutting edge. 



Lingual membrane has central plate tridentate, laterals bidentate, uncini 

 denticulated. 



Pallifera dorsalis, Binney. 

 Not uncommon. 



Buccal plate (Firj. 5,) stout, arcuate, rounded 

 at sides, having seven distinct longitudinal ribs 

 which deeply notch the cutting edge, central 

 _ one largest. 



Fl{,. 5. 

 Lingual membrane has 118-29-1-29 : central plate rather long and narrow, with 

 one long denticle flanked by two small denticles ; first ten laterals bidentate, the 

 smaller outer denticle setting off at a slight angle from the base of larger denticle, 

 the remainder of the plates tridentate, those on the extreme border of membrane 

 being wide and short with one or two short denticles. (PL 3, Fig. &.) 



HELICID^. 



HELICIN^. 



Mesodon albolabris, Say. 

 Appears to be a co'mmon s^^ecies throughout the State, though 

 not found in great numbers inland. On some of the islands in 

 Casco Bay they are met with in great abundance, the representa- 

 tives of each island showing some peculiarities of growth or color. 

 Mr. C. B. Fuller has detected a beautifid form of this species on 

 one of the outer islands in Casco Bay in company with Tachea 

 hortensi.«. The shell is rather below the average size, quite stout, 

 and deep brown or claret in color, with a broad heavy white lip. 

 On another island not far from this, the species assumed a large 

 light-yellow shell. Mr. Fuller has in his collection a specimen of 

 this species which has become singularly deformed by injuries 

 received before it had attained its complete growth. The last 

 whorl instead of proceeding in its usual course, is tui-ned completely 

 under the shell, is devoid of periostraca, and exhibits frequent 

 attempts at producing a lip. The timidity of the species when 

 first kept in confinement, is exhibited by a quick withdrawal of 

 the tentacles on being touched. It loses its timidity after a while 

 and appears quite tame. 



