54 THK NAUTILUS. 



mo8t forms) comparatively far apart ; lamellae and plicae : parieto- 

 angular not or slightly connecting with the peristome, spur small; 

 columellar rather as in typical armifera, but smaller, slighter; infe- 

 rior columellar tooth-like, placed obliquely, more constant than in 

 other forms as to size, shape and position; lower palatal regular but 

 slight, often rather short; suprapalatal rather constant. 



Alt. 3.3—3.8, rarely 4-4.2, diam. 1.9-2.2 mm.; some specimens are 

 low, almost globular, e. g., alt. 3.2, diam. 2.1 mm. 



Numerous specimens seen from Bismarck, N. D.; Eastport, la. 

 (Missouri River drift); Lincoln, Neb.; Nickerson, Kans. 



As B. a. ruidosensis, Prof. T. D. A. Cockerell ^ has denoted a 

 form from New Mexico: "Shell only 4 mm. long, with the two 

 outer teeth a considerable distance within the aperture." The de- 

 scription is somewhat meagre, but the variety may stand on its 

 merits. There are, however, specimens from various places of New 

 Mexico with the lower palatal plica rather short and rather remote 

 from the margin, the columellar rather simple and comparatively 

 small; alt. 3.8-4.2 mm.; they may be of ruidogensit. 



The interrelations of these forms will be discussed elsewhere, and 

 figures given. 



B. armifera appeared to be rather well known, being the largest 

 of the genus, fairly common over a wide territory, and probably the 

 one best represented in collections. Yet a closer study of its forms 

 has shown some interesting facts with respect to morphology, phy- 

 logeny and distribution. As Mr. Clapp expressed it, with a view to 

 this variation and the externally similar B. clappi : " We can no 

 longer say that a Bifidaria is simply armifera because it is big and 

 white." 



MOEE NOTES ON THE FAMILY PYRAMIDELLIDJE. 



BY PAUL BARTSCH, M. S., PH. D. 



In the " American Journal of Science " for June, 1909, pp. 475- 

 484, Dr. K. J. Bush reviews my paper on the "PyramidellidaB of 

 New England and the Adjacent Region," and discusses in a general 



1 The Nadtilus, XIII, p. 36. The specimen referred to is not at hand, and 

 I cannot remember exactly what it was. The type is in coll. Acad. Nat. 

 Sciences. 



