62 THE NAUTILUS. 



campamdatus rudentis Dall (See Harriman Alaska Exped., XIII, 

 p. 90). 



The citation of P. nudtivolvis from Newfoundland by Farrer in 

 1892 (Nautilus, VI, p. 36) was, as stated by him, based on a com- 

 parison with the Marl Lake shells, and his specimens are apparently 

 referable to the same variety. 



Through the kindness of Mr. E. A. Smith I have had the oppor- 

 tunity of examining specimens in the British Museum from Labrador 

 labelled " nudtivolvis." They are not that species, however, but a 

 form of P. campamdatus. 



In the summer of 1906, Dr. Chas. A. Davis of Ann Arbor, Mich., 

 while in the field for the State Geological Survey, had the great 

 good fortune to rediscover the genuine midtivolvis on the north shore 

 of Howe Lake, Marquette County, Mich., about forty miles west of 

 the City of Marquette. Nine specimens only were obtained. Three 

 of these are figured on the plate (figs. 4 and 8 to 11) and for com- 

 parison with them are given figures of one of the original specimens 

 in the National Museum (figs. 1-3) and of the specimen in the Jay 

 Collection (figs. 5-7). 



Through the kindness of Mr. L. P. Gratacap of the American 

 Museum, I have been able to make personal comparison of the latter 

 specimen with those from Howe Lake. As shown by these figures, 

 there can be no question as to the identity of the Howe Lake shells 

 with Case's species. 



Both of the original specimens figured are apparently much less 

 elevated than the Howe Lake shells, but the upper whorls of the 

 " Jay " specimen were badly eroded so that it was difficult to make 

 out the exact number of whorls, and the depressed spire of the 

 National Museum shell is evidently owing to the very irregular 

 growth, as shown in fig. 3. That some of the original lot were quite 

 as elevated as the Howe Lake specimen is shown by Sowerby's figure 

 72a, for comparison with which fig. 4 is given. The dimensions of 

 this specimen are almost exactly the same as those of Sowerby's 

 figure, and figure 4 would almost pass as an outline facsimile of the 

 other. 



It is equally clear that multivolvis is a valid species and quite dis- 

 tinct from campanulatus. Compared with the latter it is distinguished 

 by its elevated spire with more numerous and narrower whorls and 

 the wide, deep umbilicus. 



