140 ANNALS NEW YORK ACADEMY OF SCIENCES 



In its specific characters this species is intermediate between Meeko- 

 spira peracuta and Bulimorpha nitidula, and it does not exactly agree 

 with either species. According to Meek and Worthen, these types show 

 the following differences : B. nitidula has a lower spire with fewer volu- 

 tions and broader spiral angle; it is smaller, and the volutions are more 

 rounded with more deeply depressed sutures. 



The present form seems almost invariably to have a slightly broader 

 spiral angle than M. peracuta, though a certain amount of variation is 

 not absent. The agreement in this respect is then distinctly with B. niti- 

 dula. As for the convexity of the volutions, some specimens resemble 

 peracuta and others nitidula; but few, perhaps none, are quite as strongly 

 convex as in Meek and Worthen's figures of the latter species. In fact, one 

 of their figures shows this character more strongly than the other, though 

 both are drawn from the same specimen. The number of volutions is 

 more like peracuta, which is said to have 13, than nitidula, which is 

 said to have 8 or 8.5. The size is that of nitidula. none of the speci- 

 mens attaining to the length of M. peracuta. In the most essential re- 

 spect, the callus and reflexed lip, the Wewoka form agrees with M. pera- 

 cuta and differs from B. nitidula, and, if this character is regarded as of 

 generic importance, there can be no question about associating it with any 

 species but M. peracuta. Ulrich seems inclined to associate B. nitidula 

 and B. inornata with M. peracuta in his genus Meekospira, but the callus, 

 which is such a marked feature of M. peracuta, must be a generic charac- 

 ter, or its absence from the two other species accidental. This assump- 

 tion seems unwarranted, and I am referring those two species to another 

 genus than Meekospira, in which, of course, the present form must be 

 included. Though closely related to M. peracuta, I can hardly place it 

 in the same species, because of its broader spiral angle and smaller size. 



Most of the specimens referred to this species are almost absolutely 

 smooth, having but very obscure growth lines. Those from one or two 

 localities, however, are regularly marked by more or less strong incre- 

 mental lines, some of which are prominent and lend an irregularly and 

 intermittently corrugated appearance where most strongly developed. 

 Some of these shells, furthermore, show slight modifications of curvature 

 in the outer surface of the volution, which gives the spire a slightly dif- 

 ferent outline from the normal. In others, however, the shape of the 

 whorl section is entirely normal, so that no persistent difference can be 

 pointed out, save in the increased development of the stria; of growth. 

 It is possible that these sculptured specimens should be regarded as a 

 separate variety, but the differences observed hardly seem to justify the 

 distinction. 



