1028 THE PALEONTOLOGY OF MINNESOTA. 



[Euomphalidje. 



Ophiletina is a new generic or subgeueric 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 Euomphalus (the E. 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 E. cassianus, (op. 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 Pleuronotus 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 

 Lindstrom's grand work on the " Gastropoda of Gotland," in which it is referred to 

 Pleurotomaria, most authors called it an Euomphalus. In 1837 Hisinger proposed 

 the generic name Inachus 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 Pleurotomaria, nor is it, if our 

 views are correct, even a member of that family. Lindstrom admits that there are 

 "some features which remind of Euomphalus." 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 little surprise at Dr. 

 Lindstrom'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 



Its3ems tint DjKinlnek (F.i<in3 irb)ulf.. 18M.) Inteniad to replace InaclMt, Hlslnger, with PoJytropt, but as he 

 mmtlois Knin.-i'it' n -Jw'.ini 9-> sr'jy. ai th? typical sp>;le<. w'.iluh Is at lint , VITI- illy distinct from Inachus mteatus 

 i. It la urldent Hi it in<iii',i'-ri-t does not conflict with Polytropis. 



