RISSOID^S. 49 



11. Hydrobia achaja. 



Hydrobia achaja, Clessin, MalaJc. Bldt. XXV, 1878, Eubcea. 

 8 Euboeaj ex "Linnsea" and P. Bouvier, Esq. 



12. Hydrobia thiesseae. 



Hydrobia Tlriessese, Clessin (ubi 1). 



8 Euboea ; ex " Linnsea" and P. Bouvier, Esq. 

 Seems to me scarcely separable from the preceding. 



13. Hydrobia aponensis. 



Hydrobia aponensis, von Martens, Wiegm. Arch. 1867, Abano, for Paludina 

 thervnalis, Kuster, Sfc. (not of Lin.) ; sect. Thermhydrobia. 



3 Abano (Padua) ; ex " Linnaea" (as Hydr. thernialis, Lin."). 



Subgenus BYTHINELLA, Moquin-Tandon. 



J. de C. 1851, p. 239, and Hist. Moll. 1856, type Bulimus viridis, Poiret ; 

 sect. = Belgrandia, Bourg., Moll, quart. Seine, 1869, type P. gibba Drap.; 

 sect. = Vitrella, Clessin, 1877, type P. pellucida, Benz ; sect. = Frauen- 

 feldia, Clessin, 1879, type F. lacTieineri^ Clessin ; sect. = Maresia, Bourg., 

 Bull. Soc. Toulouse, 1877, type Hydr. dolicMa, Bourg.; sect. = Stimpsoma, 

 Clessin, Mai. Bldt. XXV, 1878. 



Dr. Kobelt joins the sections Maresia and Frauenfeldia ; but 

 if this is adopted, the former name must have priority. M. de 

 Folin has suggested that the group Vitrella may be the same 

 as his Locardia ; M. Bourguignat considers them as distinct : 

 if they prove identical, both names must yield priority to M. 

 Bourguignat's genus Lliotelleria, which is unmistakeably the 

 same as Locardia. 



14. Hydrobia (Bythinella) obtusa. 



Paludinella obtusa, Lea, Trans. Am. Philos. Soc. IX, 1844, Ohio ; sect. 

 Stimpsonia. 



2 New York ; coll. Prof. E. C. Stearns. 



15. Hydrobia (Bythinella) binneyi. 



Pomatiopsis Binneyi, Tryon, P. Philad. Ac. 1863, Bolinas, California ; 

 ? sect. Stimpsonia. 



20 Baulines Bay ; coll. Prof. E, C. Stearns. 



