•MOLLUSCA. 
*281 
Suborder ThalassophilA. 
Amphibolid^e. 
AmpiUlacera macuhta, sp. n., Mousson, Journ. Conch, xiii. 
p. 203, pi. 14. fig-. 3, Feejee Islands. 
Order PULMONATA OPERCULATA. 
Pfeiffer, Lud. Monographia pneumopomorum viventium. 
Supplemeiitum secundum. Cassel, 1865, 8vo, pp. 284. 
This supplementary volume contains an enumeration of all 
the species of this order, 1587 in number, and descriptions of 
those discovered since the publication of the first Supplement in 
1858, with numerous additional references to other species. The 
systematic arrangement is retained, but several new genera have 
been inserted, as Chittya (Livesay) among the Aciculaceay 
Clostophis (Bens.) among the Diplommatinacea, Rhiostoma 
y Opisthostoma {Bhila^ox^i)yHybocyst^s (Bens.) among the 
Cyclotea, Arinia (H. & A. Adams) among the Pupinea, Cyclq- 
iopsis (Blanford) and Diplopoma (Pfr.) among the Licineay Cecina 
(A. Adams) among the Realiea, Omphalotropis (Pfr.)> which 
had been made a subdivision of Hydrocena in the first supple- 
ment, forms now a distinct genus of Realiea. Japonia (Gould) 
is made a subdivision of Hydrocena. Dr. Pfeiffer persists in 
uniting in this subfamily of Realieay and probably in each of the 
genera referred to it, animals essentially different in the con- 
formation of tlie tentacles and radular teeth, as has been stated 
for Hydrocena cattaroensis and Omphalotropis maculata. Other 
species of Assiminedy with entirely similar shells, have been 
excluded from his monograph, although they had been properly 
described under the name Assiminea or Paludina ; for instance, 
A. francisci (Wood) and A. carinata (Lea), which latter is, in 
fact, the eldest name of a species described under three different 
names in Pfeiffer^s Supplement — Omphalotropis maculata yfidviday 
and fasciolata. Those Assimineee the station of which is exactly 
known live on muddy places impregnated with brackish water ; 
the true Hydrocena [H. cattaroensis) on rocks on the sea-coast, 
like Litorina ; the Realia with slender tentacles, as R. rubenSy are 
true land-shells. As far as the shells are concerned, the distinction 
between those three genera does not offer more difficulty than 
that between the genera PupOy Carychinmy and Diplommatinay 
Planorbis and ValvatOy Succinea and Limnmts. Single mistakes 
may occur, but generally the resemblance of an unknown species 
to another, the systematic place of which is already ascertained, 
will lead the careful student to a determination of its real affi- 
nity ; and it is only owing to the confusion of those genera 
throughout Dr. Pfeiffer’s and Messrs. Adams’s works that the 
names Realia and Hydrocena continue to be used as frequently 
