208 Dr. E. von Martens on the Sandwichian Species of Limnzus. 
(1847). Oblong, with flattened whorls and conspicuous colu- 
mellar plait. 
I have no specimen before me to which Gould’s description is 
entirely applicable; but the following one, differing almost 
solely by its sinistrorsity, I consider a variety of it. 
36. Limneus volutatus, b. sinistrorsus. 
L. testa sinistra, conico-oblonga, striatula, luteo-fusca, vix nitidula, 
apice truncata; anfractus superstites 3, plani, sutura superficiali, 
ultimus antrorsum valde deflexus, basi rotundatus ; apertura sat 
obliqua, piriformis, superne acutangula; peristoma rectum, tenue, 
lamina parietali distincta, crassiuscula; plica columellaris valida. 
Long. 8, diam. maj. 5, min. 4, apert. long. 5, lat. 3 millim. 
Sandwich Islands. Received many years ago from the Heidel- 
berg Museum, under the name of “ Physa, sp.” 
4. Limneus Newcombi (Erinna), H. & A. Adams, Gen. Moll. 
vol. u. pl. 188. fig. 9. 
The preceding resembles so much the Sandwich freshwater 
shell regarded as a new genus by the above authors, that I cannot 
help placing the one next to the other, although I have no 
specimen of Hrinna before me to examine. The only difference 
I can make out is that in L.. Newcombi the whorls are more in- 
volute, the last one forming almost the whole outside of the 
shell—a difference well known to exist not only between distinct 
species of European Limnet but also between the varieties of 
our most common species, L. stagnalis, as well as between those 
of L. auricularius ; in both the degree of exsertion of the spire 
is very variable. The curved elevated external ridge of the 
columella mentioned by the authors, I consider, from an inspec- 
tion of the figure, to be the columellar fold common to almost 
all species of ‘Tinmeus, but more strongly developed in L. volu- 
tatus. Erinna Newcombi is dextral. 
All the above species are of small size and dark-brown colour, 
resembling in both respects the European ZL. truncatulus, Mill. 
(minutus, Drap.), and the dwarf forms, allied to L. palustris, called 
L. fuscus. heir chief differences are combined and repeated in 
a curious crossing manner, as is shown by the following table :— 
| Whorls. Less involute. More involute. 
Convex. | Dextr. L. oahuensis, Soul. Dextr. 
Sin.? Physa reticulata, Gould} Sin. L. affinis, Soul. 
| Flat. Dextr. L. volutatus, Gould. | Dextr. EL. Newcombi, Ad. 
Sin. L. volutatus, b., mihi. Sin. 
| 
