56 A MANUAL OF AMERICAN LAND SHELLS. 



or bicuspid, of the type of tbe Helicidse. Marginal teeth quadrate, 

 with narrow base, multicuspid reflection, serrate by the splitting of the 

 inner cusi) into numerous denticles. Shell external or internal, very 

 thin, transparent, spiral. i 



Succinea. 



B. — DiTREMATA. 

 TEREESTEIA. 



Family VERONICELLID^.* 



Animal essentially terrestrial. Body limaciform, covered with a cori- 

 aceous mantle, not distinct from general integument ; head retractile 

 into an anterior cavity ; the eye-peduncles cylindrical, the tentacles 

 bifid. Genital orifices widely separated, that of the male behind the 

 right tentacle, tlie female on the lower surface of the body, near the 

 right margin of the foot, about the center of its length. Anal and re- 

 spiratory orifices on the lower surface of the body, slightly to the right. 

 Genital system with numerous multifid vesicles. Jaw slightly arcuate, 

 with numerous vertical ribs. Lingual membrane with horizontal rows 

 of teeth. Centrals narrow, unicuspid, with expanded sides ; laterals 

 large, obscurely tricuspid; median cusp sharp and long; marginals 

 with quadrate base, short, triangular, unicuspid ; no shell. 

 Veronicella. 



AQUATICA. 



Family ONCHIDIID^. 



Animal living near the sea-shore or in estuaries and covered by the 

 tide. Body limaciform, oval; eye-peduncles, but no tentacles; large 

 buccal appendages. Mantle thick, more or less tuberculous above. 

 Genital orifices widely separated, male orifice slightly to the rear of the 

 right eye-peduncle, female orifice on the infero-posterior part of body. 

 Anal and respiratory orifices on the center of the posterior end of under 

 side. Jaw entirely smooth or lightly wrinkled, only known in Onchi- 

 della. Eows of teeth on the lingual membrane oblique at center, hor- 

 izontal at edges ; central tooth tricuspid, lateral te6th and marginals 

 with quadrate base, razor-shaped; base long and with cutting point 

 narrow ; median cusp truncated and very long ; no shell. 



* Fischer uses Vaginulidoi, but that name must be reserved for the agnathous genus, 

 the true Vaginula. 



