RISSOIDE. 49 
11. Hydrobia achaja. 
Hydrobia achaja, Clessin, Malak. Blt. XXV, 1878, Eubea. 
8 Eubeea; ex “Linnza” and P. Bouvier, Esq. 
12. Hydrobia thiessez. 
Hydrobia Thiessex, Clessin (ubi 2). 
8 Eubeea ; ex “ Linnea” and P. Bouvier, Esq. 
Secms to me scarcely separable from the preceding, 
13. Hydrobia aponensis. 
Hydrobia aponensis, von Martens, Wiegm. Arch. 1867, Abano, for Paludina 
thermalis, Kister, Sc. (not of Lin.) ; sect. Thermhydrobia, 
3 Abano (Padua) ; ex “ Linnwa” (as “ Hydr. thermalis, 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 L. gibba Drap.; 
sect. = Vitrella, Clessin, 1877, type P. pellucida, Benz ; sect. = Frauen- 
feldia, Clessin, 1879, type F. lacheineri, Clessin ; sect. Maresia, Bourg., 
Bull, Soc. Toulouse, 1877, type Hydr. dolichia, Bourg. ; sect. = Stimpsoma, 
Clessin, Mal. Blét. 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 Lhotelleria, 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 ; 
2 sect. Stimpsonia. 
20 Baulines Bay ; coll. Prof. E. C. Stearns. 
