RISSOID^. 63 



Clessin, in tlie JiTacliriclitsblatt for 1878, p. 126, considers 

 Lartetia^ Bourguignat, as a close ally, and tliat both should 

 constitute a family between the Rissoidse and Melaniidce ; in 

 1880 he classes the group as part of the latter. 



1. Baikalia stiedse. 



Leucosia Stiedre, Dyboivski, Acad. Imp. St. Petersburg, 1875, Lake BaiJcal ; 

 sect. LiohaiJcalia. 



1 Lake Baikal ; ex Mr. R. Damon, 



Genus TRACHYBAIKALIA, von Martens \_emend.'\ . 



JaTirh. Mai. Ges. 1876, for Ligea, jDyhowski, 1875, type T. costata, Dyh. \jiot 

 of Fabricius, genus Crust.'] ; sect. = Godleivskia, Crosse and Fischer, 

 J. de C. 1879, type T. tiirriformis, Dyb.; belongs to Fam. Melaniidce, fide 

 Clessin. 

 Not rejaresented in the Museum. 



Subfamily SKENEIN2E, Stimpson. 



Genus SKENEA, 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 FOMATIOPSIN^, Stimpson. 



Genus POMATIOPSIS, Tnjon. 

 F. Philad. Ac. 1862, p. 452, type Faludina lapidaria. Say. 



1. Pomatiopsis lapidaria. 



Paludina lapidaria. Say, J. Ac. Nat. Sci. I, 1817, Ilissouri to Michigan. 



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

 12 Michigan ; coll. Prof. W. Newcomb. 



2. Pomatiopsis intermedia. 



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

 4 Oregon ; coll. Prof. W. Newcomb. 



