1915.] NATURAL SCIENCES OF PHILADELPHIA. 343 



there is decidedly more vegetation. A few were picked up on the 

 slope towards Station 10, dead shells being scattered all over the 

 upper 500 ft. or more of this ascent. 



Sixty specimens were opened, measurements of 31 being given below. 



(1) No axial lamella, merely a callous or very inconspicuous node 

 on the axis in the penultimate whorl. 15 individuals = 25%. 



Length 14, diam. 4 mm.; whorls 13; penult, whorl smooth. 



(2) Axial lamella in penultimate whorl short and strong; no other 

 lamellae. 30 individuals = 50%. 



(3) Axial lamella short and strong or rarely weak; a basal lamella 

 within last half of penultimate whorl. 12 specimens = 20%. 



(4) Axial, basal and superior lamellae in the last half of penulti- 

 mate whorl. 3 individuals = 5%. 



Length 14, diam. 4 mm. ; whorls 13 ; penult, whorl weak ribs. 

 " 13, '' 4 " " 12|; " " strong ribs, 



" 12.7, '' 4.1 " " 121; u a gn,ooth. 



