GASTROPODA. "'"' 



I-opbo.pl rm obllqak.) 



improbable that the idea of an abrupt ret nil mrvo (if the ^tri.i- was received from 

 some similar associated but distinct shell. That he united more than one species or 

 variety under the name bicincta is shown, provided the form has been correctly 

 drawn, by bis figures bg and A. In the first, representing the fossil of the natural 

 size, no upper carina is shown; nor is the peripheral angle trilineate. The second 

 represents a part of the last whorl magnified and shows not only one, but two 

 carina? on the lower half. Perhaps these figures are not entirely trustworthy. 



Although very frequently quoted, we thought it best to restrict the synonomy 

 of the species to the original description, because we found it almost impossible to 

 decide in most instances whether an author had the true bicincta before him or not. 

 With collectors the practice prevails to a large extent to identify almost any set of 

 Lower Silurian L'/;i/i">/uV</ with the bicincta, and we have seen no less than ten 

 di-tinct species in collections bearing the one label " Murchisonia bicincta Hall." 



r's M. bicincta (Can. Org. Item., Dec. 1, p. 19; 1859) clearly belongs to the next 

 species or variety (L. obliqua) while Meek and Worthen's (Geol. Sur. 111., vol iii, p. 

 317; 1868) we describe as another new species under the name L. perforate. Then 

 the Upper Silurian shell from the island of Gothland, which LindstrOm identifies 

 with this species (be calls it a PUurotomaria) and describes and figures so beautifully 

 in his classical work on the Gastropoda (Up. Sil. Gastropoda of Gotland, p. 106, pi. 8; 

 1884) is most certainly not the same as the American species. We have specimens 

 of the Gothland shell before us and can say most emphatically that it has scarcely 

 a single specific feature in common with L. bicincta. Comparing it with the other' 

 American species of Lophospira, we find that while it resembles L. sumnercnsis 

 Safford more than any of the others, it is still readily distinguished. 



The essential characters of L. bicincta, as here identified and restricted, are (1) 

 the ventricose whorls, (2) the sharp and regular lines of growth, and (3) the exceed- 

 ingly shallow sinus in the outer lip and vertical direction of the surface striae from 

 the peripheral band downward. 



>'r ..:. and Jocnhn/. Tr.Titon p-ri<Kl, Stone.* Km-r irruup, not uncommon In the "Central lime- 

 T.fstN,rn. T.-nnewee, and rather rare in 1 1 rula bed at Minneapolis, Minnesota, 



an(1 B.- ' Black I ' .nty. Kentucky: Tr.-n ton jr 



rk: QUtamboaitM and Kusispira beds at several localltle* In <;.-..ihu- ,!, 

 ota: Cincinnati i-rio.1, Ki.-hmoi, ring Valley and "th-r localities In Flllmore county. 



.-K. O. Ulrlch. 



LopiinsriKA OBi.ivit-A. n. $f>. <r/nV/u 



H.ATK I.XMI. rios.*-*. 



SALTBR, 1859. Can. Org. Hem., Dec. I, p. 19. (Not M. btcineta HALL, 1847.) 

 This form agrees in all respects with /,. bisinrta excepting that the surface striae 

 are less sharp and not so regular, and that instead of passing vertically downward 



