1028 THE PALEONTOLOGY OF MINNESOTA. 
([Euomphalide. 
Ophiletina is a new generic or subgeneric name proposed by us for the reception 
of two or three peculiar yet obviously euomphaloid shells occurring in the Stones 
River, Black River and Trenton groups in Minnesota and elsewhere. Compared with 
other types of the family, we find that they resemble certain Carboniferous species 
of Luomphalus (the HL. subquadratus section) more closely than any others found in 
Paleozoic rocks. Nearer even than these is a Triassic species which Koken figures 
and describes as LV. cassianus, (ops.cit.,.p. 416). Now, we consider it quite out of the 
question that either the Carboniferous or the Triassic species are descended from 
the Lower Silurian shells under consideration. What we do believe is that Ophiletina 
is a rapidly evolved side branch from Ophileta that became extinct before or with 
the close of the Lower Silurian age. The principal reason for this opinion lies in 
the fact that no shell of this type is known from the Upper Silurian, nor from the. 
Devonian, unless Plewronotus be so considered. The latter, however, is more like 
Ophileta than Ophiletina, 
Hisingeria is proposed for the reception of Inachus planorbis His., a well known 
fossil of the Upper Silurian strata of the island of Gotland, that, since 1828, when 
Hisinger first identified it with Wahlenberg’s Turbinites centrifugus, has been referred 
to under no less than seven different generic names. Until the appearance of 
Lindstrém’s grand work on the “Gastropoda of Gotland,” in which it is referred to 
Pleurotomaria, most authors called it an Huomphalus. In 1837 Hisinger proposed 
the generic name Jnachus for it, but as this had been used many years before by 
Fabricius, it could not be retained.* Believing that Hisinger was fully justified in 
separating his species planorbis (or sulcatus, as he often called it) from previously 
established genera, it seems to us only a just recognition of his acumen to substitute 
Hisingeria for his Inachus. We may add that Koken (op. cit., p. 419) also regards the 
species planorbis as “the representative of an independent genus.” 
Hisingeria planorbis is most certainly not a true Plewrotomaria, nor is it, if our 
views are correct, even a member of that family. Lindstrém admits that there are 
“some features which remind of Huomphalus.” We should say many instead of 
some, and add that we have not found a single character that may be justly set 
against them. That Hisingeria has a deeply notched aperture and a kind of slit- 
band is no more indicative of pleurotomarian than euomphaloid affinities, and when 
we consider that the detail of the band, together with every other feature of the 
shell, is more in accordance with the latter than the former, a littie surprise at Dr. 
Lindstrém’s positive reference of H. planorbis to Pleurotomaria may be pardoned. 
The form of the shell is decidedly euomphaloid, as is also the position of the band on 
*[tssams that DsKoninek (Mauna Oarbvdonif., 1831.) intended to replace Inachus, Hisinger, with Polytropis, but as he 
meiatiors Bimp vis dissors Sowerby. ai the typicalsp3zies, waich is at laa3st generically distinct from Inachus sulcatus 
(planorbis), itis evident thit Hisinyeria does not conflict with Polytropis. 
