Miscellaneous. 393 
This discovery, the first and only one of the kind in Styria, leads 
directly to that diluvial period when, by the extension of the 
glaciers in the higher regions of the Alps, the Upper Alpine animals 
and the Alpine flora were driven down into the low grounds, the 
evidences of which have hitherto been detected chiefly in Switzerland. 
— Bericht der Akad. der Wiss. in Wien, March 8, 1866, p. 46. 
Researches upon the Hydrobiinee and allied forms ; chiefly made 
upon Materials in the Museum of the Smithsonian Institution. 
By Dr. Wriuram Stimpson. 
The great difficulty of studying the anatomy of the Hydrobiinee, 
owing to their diminutive size, has, with few exceptions, caused 
conchologists to classify them merely from the form and other cha- 
racters of the shell, and such parts of the animal as can be seen pro- 
truded when in motion. Hence rather widely different views have 
been entertained in regard to their generic relations, some referring a part 
of them to the genus Paludina, others to Melania, Leptoxis, OCyclo- 
stoma, &c., while other authors have more properly proposed for the 
reception of certain types the genera Amnicola, Pomatiopsis, Soma- 
togyrus, &e. Even those who have admitted these new genera, how- 
ever, still differed in regard to their family affinities, some placing 
certain of them in the Melaniide, others in the Rissoide, Viviparide, 
Littorinide, &e., while still other conchologists proposed to establish 
for their reception a new family, Amnicolide. 
After a thorough and searching investigation of the whole subject, 
particularly of the structure of the softer parts and the dentition of 
many of these types, Dr. Stimpson arrives at the conclusion that these 
little snails all belong to the Rissocde, to which they had in part 
been referred by H. & A. Adams; though he also includes in the 
family the genera Lithoglyphus and Paludestrina (referred by those 
authors to the Littorinide), as well as several new genera he finds it 
necessary to establish. He likewise suggests that Pyrgula, Tricula, 
Cecina, and Blanfordia probably belong to this group; while he 
excludes from it the genus Barleea, which had been included by 
H. & A. Adams. 
After thus eliminating the extraneous genera, and including others 
not previously known to belong to this family, he gives a full and 
clear diagnosis of the group, by which it can readily be distinguished 
from the families Littorinide, Viviparide, Truncatellide, Melaniide 
and Valvatide, with which it is more or less nearly allied, or has in 
part been confounded. He then defines the following six subfamilies, 
into which the group is found to be naturally divisible :— 
. Bythiniine, including Bythinia, Gray. 
. Rissoinine, including Rissoina, D’Orb. 
. Rissoine, inciuding Rissoa, Frém., Cingula, Flem., Alvania, Risso, 
and Onobia, Setia, Ceratia, and Fenella, H. & A. Adams. 
. Skeneine, including Skenea, Flem. 
Hydroliine, including Hydrobia, Hartm., Littorinella, Braun, 
One 
oe 
