GEOGRAPHICAL DISTRIBUTION. 
Moll. 27 
(very doubtful), Sphcuriam 2, Pisidiiim 1, Unio 5 spp. — in all, 75 inoper- 
culated and 9 operculated terrestrial, 13 inoperculated, 10 operculated, 
and 8 bivalve freshwater, and 8 brackish water species — are enumerated 
and briefly described by F. W. Hutton, Manual of the New Zealand 
Mollusca, pp. 5-40, 78, 81, 82, 90, 154, 155, 160 & 161. The genera 
marked with an asterisk are peculiar to New Zealand, p. iii. 
Polynesia. 18 species of Pupa enumerated, 7 of them belonging to the 
new group Ptychochilus^ 2 to Cylindrovertilla^ 2 to Leiicochilus, 1 to 
Tesseraria (see special part), the rest not known to the .author, enume- 
rated by Bottgeu, in Martens's Conchol. Mitth. pp. 45-72, 7 witli several 
varieties figured, pis. x.-xii. P . p>ediculus (Shuttl.) generally distributed 
on the Polynesian Islands. 
Caroline Islands. 9 species of land shells collected by 0. Finsch on the 
Islands Ponape and Ruck ; 2 are new, of which Tornatellina gigas and 
the known Nanina sowerbiana (Pfr.) are of remarkably large size among 
the Polynesian species. A Scarahus of these islands appears not distinct 
from the known imhriuni (Montf.) of the Philippine and Malayan Archi- 
pelago. E. V. Martens, SB. nat. Fr. 1880, pp. 143-147. 
13 . North America. 
Arctic species, see before — 1. Arctic Region. 
A. G. Wetherby discusses the geographical distribution of the Strepo- 
matidoi (Melaniidce) and Unionidee in North America, and sums up the 
following chief results : — 
(1) The small number of species of Unionidee and the entire absence 
of Strepomatidee in the New England States, and the fact of the distri- 
bution of some of the former entirely across the continent to the Pacific 
coast and southward along the Atlantic. 
(2) The introduction (appearance) of the Strepomatidee west of the 
Green Mountain mass, and their division into two geographical groups, 
one pertaining to the western, the, other to th«'. southern fauna. 
(3) The continuance of the Ohio types of Unionielec westward, north of 
that stream, to the limits of the Mississippi drainage, and south and 
south-westward to western Texas, and the comparative absence of Strepo- 
rnatidee over this area. 
(4) The introduction of now species in both families, and of new 
genera in the Strepomatidee, so soon as we cross the Ohio and travel south. 
(5) The facies of the groups of species which the streams of this part 
of the Ohio drainage contain, stamping them as different faunas. 
(6) The anomalous fauna of the Alabama drainage, and especially the 
fact of its geographical isolation. The two genera Schizostoma and Tulo- 
stoma and several peculiar groups of Goniohasis are confined to it. 
(7) The special cases of the only species of spinous Unio known, U. 
spinosus (Lea), only in Altamaha river at the southern end of the eastern 
slope of the Appalachians, and U. collinus (Conrad), only in New river, 
on the western slope of the same, and that of Margaritana margaritifera 
(L.), the only species of Unionidee which is common to Europe and North 
America. 
1880 . [voL. XVII.] 
B 10 
