1915.] NATURAL SCIENCES OF PHILADELPHIA. 337 



Length 18, diam. 5 mm. ; whorls 16 



(3) Three lamellae, superior, axial and basal. Six individuals 

 = 10%. 



Length 20.5, diam. 4.9 mm.; whorls 17 

 " 20 " 5 '' " 17| 



u 20 " 4.9 " " 17 



■" 19.5 " 4.9 " " 17 



U ^Q U 5 U U ^7 



In size, sculpture and shape, we can find no external character 

 correllated with the differences in internal structure. The speci- 

 mens from Station 5 are from one colony. 



It will be seen that the typical bilamellata axial structure pre- 

 dominates, nearly 70% having that arrangement of lamellae. The 

 dimensions of this lot agree well with those given by Bartsch for 

 8 specimens in the U. S. Nat. IMus., but our lot, being larger, includes 

 shells both larger and smaller than any in the original lot. 



Holospira bilamellata longa n. form. Plate VII, figs. 2 to 26. 



Slender and pillar-like, the diameter contained four times or more 

 in the length ; whorls of the cone and last whorl costulate, 3 to 5 inter- 

 mediate whorls usually smooth or nearly so. Aperture projecting 

 laterally and forward; usually 3 internal lamellae, in the beginning 

 of the penultimate whorl, therefore ventral in position, the superior 

 lamella generally very strong, and larger and longer than the basal. 



Length 19.6, diam. 4 mm.; whorls 17 

 " 19.2, '' 4 " " 18| 



" 18.7, " 4 " " 17i 



99 



