166 
MOLLUSCA. 
Planorbis mahilli, sp, n., Bourguignat, R. Z. 1870; p. 28; Angy, department 
of the Oise. Allied to corneus (L.). 
Planorbis riparius, VVesterlund, and aci’es (Mhflld.); their differences from 
allied specieS; and their occurrence in Northern Germany; Reinhardt; Nadir, 
mal. Ges. iL pp. 6, 7, and 21-25. — PI. vortex, var. discoides, v. n.; Reinhardt, 
ibid. p. 24. Westerlund gives a note concerning his determination of PL 
discus (Parreyss); ibid. p. 67. 
Planorbis sudanicus, sp. n.; Bahr-el-ghazal system of the White Nile, 
allied to the American group of PL guadelupensis. Martens, Mal. Bl. xvii. 
p.36. 
Planorbis fouqueti, sp. n., J. de Conch, xviii. p. 146, New Caledonia. 
Planorbis trivolois, Say. Photograph of its dentition by Binney and Bland, 
Ann. l^yc. N. York, ix. p. 292. 
Carinifex newberryi, Lea. Lingual dentition described and figured by Ball, 
Ann. Lyc. N. York, ix. p. 345, and pi. 2. fig. 14. 
Ancylus fiuviatilis, var. dimidiatus, rividaris, lepidus, and depressus, v. n. 
Colbeau, L c. p. 103, pi. 2. figs. 12-15. 
Poeyia, Bourg., is supposed to be the young state of Gundlachia, and An- 
cylus ciimingianus, Bourg., that of Latia, by Dali, L 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 Avith that of Helix 
and Limnaea in the principal features, are confirmed by his 
researches. He divides the genus into two sections : — 
A. Siphonaria proper. Shell solid, porcellanous, radiatoly 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., peltoides, Carp., pi. 4. fig. 11, extending from Monterey to 
the Galapagos, and including perhaps as varieties Nacclla subspirulis. Carp., 
and N. vernalis, Dall. Most of the species are extratropical. Anisomyon, 
Meek, I860, appears to be a genus allied to Siqdionaria. Dall, Am. J. Conch, 
vi. pp. 30-41, pis. 4, 6. 
Gadinia, Gray. The anatomical examination of a west-coast 
species, G. reticulata, Sow., by YV . 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 shoAVS affinity with the 
Aur'iculidee ; and the dentition has relations Avith that of Sipho- 
naria. The rostrum is bifid and infundibuliform. 
The known species arc: — G. afra (Ginel.), Western Africa; garnotii 
