THE NAUTILUS. 



VOL. XI. APRIL, 1898. No. 12. 



DESCRIPTIONS OF NEW AMERICAN LAND SHELLS. 



BY HENRY A. PILSBRY. 



Punctum clappi n. sp. 



Shell minute, openly umbilicated, yellowish-brown, with depressed, 

 nearly level spire, and cylindroid whorls. Whorls 3J, the earlier 

 H sraoothish, finely pitted, the last 1 or 11 whorls sculptured with 

 elevated laminte running with the increment-lines, 30 to over 40 on 

 the last whorl, the intervals closely striated and showing fine spiral 

 striation ; suture impressed, descending in front; umbilicus deep 

 and open, its width contained between 83 and 3i times in greatest 

 diameter of shell. Aperture short oval, higher than wide, somewhat 

 oblique, but little excised by the previous whorl. 



Alt. I'l~r2, greatest diam. 2 mm. 



Seattle (Randolph) and Tacoma (Hemphill), Washington ; Salem, 

 Oregon (Hemphill). 



My attention was called to this form some years ago, but its de- 

 termination at this time is due to Mr. George H. Clapp, who insist- 

 ing that the shells were neither Punctum conspectum nor Pyramidula 

 astericus, induced me to review the group. 



P. (Planogyra) asteriscus is even flatter above ; the umbilicus is 

 wider, one-third the diameter, and more open ; the cuticular lamellae 

 are more widely spaced and fewer, 1 9-25 on the last whorl, and the 

 aperture is relatively smaller. 



Punctum conspectum, which also occurs at Seattle, has a much 

 more elevated spire, decidedly narrower umbilicus, less than one- 

 fourth the diameter of the shell, and the aperture is different in 

 shape, wider than high. 



