46 Obs&t'vations on tke Terrestrial 



AMNICOLIDJE. 

 Amnicola limosa, Say. 

 Very common. The animal agrees precisely with Say's de* 

 scription, except that he does not mention a white line running 

 along each tentacle* 



Amnicola porata, Say. 

 Not so common as the preceding* 



Amnicola decisa) Hald. 



A species agreeing precisely with Haldeman's figure ahd dg* 

 scription, occurs in the vicinity of Portland. 



VALVATID^. 

 Valvata tricarinata, Say. 

 Very large specimens of this species were found in abundance 

 at Bowdoinham ; also dredged in Mud Lake, in the northern part 

 of the StatCk 



Valvata sincera, Say. 

 Dredged in Mud Lake, N. Lat. 47°^ Have it also in abundance 

 from Lawler's Lake, seven miles from St. John, N. B., through 

 the kindness of Mr. Verrill. Among the specimens in this lot 

 are many in which the whorls are entirely separated from each 

 other, giving the shell a most singular appearance. 



Lyogyrus pupoideaj Gould. 

 Occurs rarely in the southern portions of the State. Amnicola 

 lustrica, Say, is probably the immature form of this species» I 

 have specimens answering perfectly to Say's description of Amni- 

 cola lustrica, which has an orbicular operculum, and I can detect 

 no difference between these and the young of V. pupoidea. Say 

 in his description of A. lustrica, expresses the opinion that it 

 might be referable to Valvata. He was led to this opinion by 

 the circular aperture. 



