1893.] NATURAL SCIENCES OF PHILADELPHIA. 271 



Further studies of more material of all these forms will be neces- 

 saiy.* 



11. V. perspectiva, n. sp., 29 PL VIII, fig. F. Man. Conch., PI. 33, fig. 39-46. 



Shell small, with very wide perspective umbilicus, more widening 

 for the last h whorl, flat, or a little elevated above, with rather dense, 

 somewhat regularly set, moderately strong membranous ribs (about 

 35 on the last whorl) and with finer striae between them ; nucleus 

 without revolving lines; pale horn to colorless, thin, translucent; 

 whorls 3J, gradually increasing, a little flattened above and below 

 the periphery, with a deep suture, the last rounded, comparatively 

 narrow, little expanding toward the aperture, rather rapidly 

 descending in toto ; aperture very inclined and oblique, almost tan- 

 gential, transversely (short) ovoid or oblong ; peristome continuous, 

 shortly but not abruptly everted except near the suture, without (or 

 with a very thin) lip. 



Diam. maj. 2*0, min. VI, alt. 0*7 mm. 



Soft parts as usual in the genus ; the liver, as seen through the 

 shell, appears' grayish brown. Jaw slightly arcuate, with rather 

 fine irregular ribs. Radula with 77 transverse rows of 25 teeth : 

 R : 3-J-2 : 7. There are 3 perfect laterals and the fourth resembles 

 them closely, yet forms the transition from laterals to marginals, 

 and even the fifth might rather range with the former, as its plate is 

 distinct though small ; its ectodont is two-pointed, and the pecul- 

 iarly-formed mesodont rather long. The sixth is a marginal, with 

 2 distal cusps ; the other marginals are wide and short, with 4 to 6 

 slender cusps, the mesodont being moderately longer than the 

 others. The last 1 or 2 are very small, and their cusps indistinct even 

 when highly magnified. 



This is a North American species, which I saw first from Knox- 

 ville, Tennessee, where it had been collected by Mrs. Judge 

 Andrews in damp moss on the cliffs above the Holston River. 

 Later it was found in Jackson County, Alabama, by Mr. H. E. 

 Sargent, and, among the specimens sent, there were a few living, so 

 that I could observe the animal and examine at least the jaw and 

 radula. Doubtless our species will be found at more localities in 

 the Appalachian Mountains. In the Missouri River drift, from 

 Eastport, Iowa, mentioned under V. parvula, there were four exam- 

 ples of this species, somewhat small, 1*8 and 1*9 mm. diam. 



*See Appendix. 



29 S. notice in "Nautilus," V, No. 4, p. 101. 



