THE NAUTILUS. 



VOL. XXIV. MAY, 1910. No. 1 



ON THE VARIATION OF APLTJSTBUM AMPLUSTRE LINNE. 



BY CATHARINE J. BUSH, PH.D. 



Zoological Depaitment, Yale University Museum. 



A short series of exceptionally fine specimens of this species has 

 recently been presented to tha Yale University Museum by Mr. 

 Bruce Cartwright, Jr., '05. They were collected by him on Ham- 

 mer Point, Pearl Harbor, Oahu, Hawaii, where they were quite 

 common in the sand under coral and lava rocks. 



The largest is eleven-eighths inches long and seven-eighths broad, 

 and the smallest a little over seven-eighths inches long and five- 

 eighths broad. There is considerable variation in the height of the 

 epire ; in the largest example each whorl, beyond the minute tilted 

 and partly immersed nuclear one, is a little raised, forming a well 

 elevated spire of about five-sixteenths of an inch in height. In 

 others the early whorls are coiled in the same plane, forming an ob- 

 tuse apex, and in one the coiling is reversed so that the early whorls 

 are sunken. There is also great variation in the exposure on the last 

 whorl. The pink and white color bands do not noticeably differ in 

 width, but the black lines bordering them do vary, and in one in- 

 stance an additional black line appears in the middle of the peripheral 

 white band. There is also great variation in the forming of the inner 

 lip of the aperture. In some of the specimens it closely adheres to 

 the body of the shell and has an irregular outline with a free edge, 

 which forms a distinctly lamella-like margin, or outer wall, to a 

 deep open canal extending the entire length of the columella. In 

 others it is seen only as an adherent patch just beneath the suture 



