RISSOID^. 63 



Clessin, in the Nacliriclitsblatt for 1878, p. 126, considers 

 Lartetia^ Boiirgiiisfnat, as a close ally, and tliat Lotli should 

 constitute a family between the Rissoidee and Melaniidge ; in 

 1880 he classes the group as part of the latter. 



1. Baikalia stiedse. 



Leucosia Stiedse, ByloivsJci, Acad. Imp. St. Petersburg, 1875, Lake Baikal ; 

 sect. LiohaiJcalia. 



1 Lake Baikal ; ex Mr. R. Damon, 



Genus TRACHYBAIKALIA, voyi Martens lemend.]. 



Jahrh. Mai. Ges. 1876, for Ligea, ByhoiosJci, 1875, type T. costata, Dyh. \_not 

 of Fahricius, germs Crust.'] ; sect. = Godlewskia, Crosse and Fischer, 

 J. de C. 1879, type T. tiirriforinis, Byh.; belongs to Fam. 3Ielaniidce,Jide 

 Clessin. 

 Not represented in the Museum. 



Subfamily SKENEIN^, Stimpson. 



Genus SKENE A, Fleming. 

 Hist. Brit. Anim. 1828, type Turbo planorbis, Fabr. 



1. Skenea planorbis. 



Turbo planorbis, O. Fabricius, Fauna Greenland, 1780. 



8 England ; coll. G. Nevill, Esq. 

 10 England; ex Mr. R. Damon. 



Subfamily FOMATIOPSINJ]], Stimpson. 



Genus POMATIOPSIS, Tryon. 

 P. Bliilad. Ac. 1862, p. 452, type Paludina lapidaria. Say. 



1. Pomatiopsis lapidaria. 



Paludina lapidaria. Say, J. Ac. Nat. Set. I, 1817, Missouri to Michigan. 



18 Niagara Falls ; coll. Prof. E. C. Stearns. 

 12 Micliigan ; coll. Prof. W. Newcomb. 



2. Pomatiopsis intermedia. 



Pomatiopsis intermedia, Tryon, Am. J. Conch. I, 1865, S. F. Oregon. 

 4 Oregon ; coll. Prof. W. Newcomb. 



