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THE - CONCHOLOGISTS’ > EXCHANGE 
Helix Darnaudi, Pfeiffer; H. Issel. 
H. Jickeliana, Nevill, etc. 
Types: 
iana, Morelet ; 
Geog. distribution : 
nia ; Sennaar. 
Mountains of Abyssi- 
XX. Pseudiberus, Ancey. ‘Testa solida, 
“opaca, non nitens, costulata vel striata. Spira 
“plus minusve elevata, obtusa; anfractus 
‘parum convexi, interdum carinati, sutura 
“lineari, modice crescentes ; ultimus carinatus. 
“Apertura obliqua angulata. Peristoma album 
‘reflexum, incrassatum. MHabitu et textura 
“testae Iberos (Europe incolas) valde com- 
‘“memorans: Umbilicus apertus.” 
Types: Helix tectum-sinense, Mart.; H. 
Zenonis, Gredler; H. plectotropis, Mart., and 
Matsianensis, Nevill. 
Geog. distribution: China (in Northern 
provinces); Central Asia (Eastern Turkestan, 
Songoria, Mounts Tian-schan). 
Allied to Plectotropis; more coarsely sculp- 
tured, shell heavier, peristome thicker and 
whitish; the texture of the shell is quite differ- 
ent and the general appearance is much like 
that of Helix scabriuscula. 
XXI. 
I venture to suggest the above name for 
the well-known @alifornian species of Helices 
such as arrosa, Gould; ramentosa, Gould; 
exarata, Pfeiffer; tudiculata, Binney, and 
others, as Dr. Jousseaume has proved they are 
distinct from the European type of Arionta 
(Helix arbustorum), by many features of the 
soft parts. He has studied Helix tudiculata, 
so that this species must be regarded as the 
type of the group. It bears the same relation 
to Aglaja and Lysince, as in Europe Arionta 
to Campylosa, and I am convinced the 
two series are parallel in both countries. 
Micrarionta, Ancey, a group including only 
three Californian species, viz: H. Gabbi; 
H. facta. and H. ruficincta, Newcomb, is very 
near Helminthoglypta, and connects it with 
Aglaja.. 
Helminthoglypta, Ancey. 
To be continued. 
THE SHELL-BEARING MOLLUSCA 
OF RHODE ISLAND. 
BY HORACE F. CARPENTER. 
(Nore. This article is a continuation of the same sub- 
ject as formerly published in ‘‘Random Notes on 
Natural History.’’—Epziror.) 
Chapter XXXVI. 
| 182. Planorbis (Menetus) exacu- 
tus, Say. 
Synonyms: Planorbis, lens, Lea ;_ Planorbis 
Brongniartiana, Lea; Planorbis leiticularis, 
Lea; Planorbis Buchanensis, Lea; Planorbis 
hyalina, Lea. 
This very peculiar shell was discovered in 
Lake Champlain by Mr. Augustus Jessup. 
Only two specimens were found and these 
were deposited in the cabinet of the Academy 
of Natural Sciences, at Philadelphia. Mr. Say 
described them in 1821, in the ‘Journal of the 
Academy,” Vol. II, No. 165, under the name 
of Planorbis exacuous. This term is not a Latin 
word, nor has ita Latin termination and it may 
be presumed that in printing the description, an 
“o’? was substituted in mistake, for a ‘‘t.’’ 
If so, by correcting this error, we have a legiti- 
mate specific name, and one very expressive 
of the form of the shell. The subgeneric 
name, Menetus, includes those species whose 
shells are depressed ; whorls rapidly increasing; 
the periphery angulated, and the aperture very 
oblique. It was used by A. and H. Adams, 
in 1885, for two species of Planorbis inhabit- 
ing the United States, planorbis opercularis, 
Gould, and exacutus, Say. 
The shell is of a light horn color, those 
from some localities almost white, with four 
whorls, flattened so that each whorl is twice as 
wide as deep; the upper and lower surfaces 
are both convex and meet at the periphery in 
an acute lateral edge; the superior termination 
of the lip exactly coincides with tne sharp 
edge of the body whorl ; the aperture, looked 
