"^'iSi!^,i:t" ^MMm in the Uni.

166
MOLLUSCA.
Planorbis mabitti, sp. n., Bourguignat, R. Z. 1870, p. 28, Angy, department
oftheOise. Allied to corneus (L.).
Planorbis riparius, Westerlund, and acies (Mhflld.), their differences from
allied species, and their occurrence in Northern Germany, Reinhardt, Nachr.
mal. Ges. ii. pp. 6, 7, and 21-25.—PL vortex, var. discoides, v. n., Reinhardt,
ibid. p. 24. Westerlund gives a note concerning his determination of PI.
discus (Parreyss), ibid. p. 57.
Planorbis sudanicus, sp. n., Bahr-el-ghazal system of the White Nile,
allied to the American group of PI. guadelupensis. Martens, Mal. Bl. xvii.
p. 35.
Planorbisfouqueti, sp.n., J. de Conch, xviii.p. 146, New Caledonia.
Planorbis trivolvis, Say. Photograph of its dentition by Binney and Bland,
Ann. Lye. N. York, ix. p. 292.
Carinifex newbeiryi, Lea. Lingual dentition described and figured by Dall,
Ann. Lye. N. York, ix. p. 345, and pi. 2. fig. 14.
Ancylus fiuviatilis, var. dimidiatus, rivularis, lepidus, and depressus, v. n.
Colbeau, /. c. p. 103, pi. 2. figs. 12-15.
Poeyia, Bourg, is supposed to be the young state of Gundlachia, and Ancylus
cumingianus, Bourg., that of Latia, by Dall, I. c. p. 358.
THALASSOPHILA.
Siphonaria. The anatomy of this genus has been the subject
of researches by WM. DALL, chiefly in S. tristensis (Sow.). He
found several differences from the previous description by Quoy
and Gaimard ; but the chief systematic characters, as the united
sexes, the lungs, and the radula agreeing with that of Helix
and Limncea in the principal features, are confirmed by his
researches. He divides the genus into two sections :—
A. Siphonaria proper. Shell solid, porcellanous, radiately ribbed, apex
central or subcentral. S. gigas, Sow., sipho, Sow., and alternata, Say. Most
of the species tropical.
B. Liriola. Shell thin, horny, smooth, or finely striated; apex marginal
or submarginal, twisted to the left in most of the species. S. thersites, Carp.,
the northernmost species, occurring at Sitka and Alaska; S. tristensis, Sow.,
lessoni, Blainv., and peltoides, Carp., pi 4. fig. 11, extending from Monterey to
the Galapagos, and including perhaps as varieties Naeella subspiralis, Carp.,
and N. vernalis, Dall. Most of the species are extratropical Anisomyon,
Meek, 1860, appears to be a genus allied to Siphonaria. Dall, Am. J. Conch.
vi. pp. 30-41, pis. 4, 5.
Gadinia, Gray. The anatomical examination of a west-coast
species, G. reticulata, Sow., by W. DALL proves that this genus is a
true pulmonate, breathing air by means of a lung, and unprovided
with gills of any kind. The anatomy shows affinity with the
Auriculidce; and the dentition has relations with that of Siphonaria.
The rostrum is bifid and infundibuliform.
The known species are :— G. afra (Gmel), Western Africa; garnotii