THE NAUTILUS. 125 



Genus SPINEOTEREBRA Sacco, 1891. 



A. Sulcus absent, suture appressed. 



a. Columellar border callous, axis impervious. Spineoterebra. 



b. Columellar border bare, axis pervious. 1 Mazatlania. 



This table is not intended to exhibit all, or even the more import- 

 ant characters upon which the main subdivisions (which will be 

 treated elsewhere) are based, but is rather a key by which the shells 

 may be conveniently assorted. The sections are typified as follows : 



Strioterebrum Sacco, 1891. T. basteroti Nyst. 



A recent example is T. dislocata Say. 



Fusoterebra Sacco, 1891. Fusus terebrina Bonelli. 



A recent example is T. benthalis Dall. 



Perirhoe Dall, 1908 (nov.). T. circumcincta Deshayes. 



An American example is Acus rushii Dall. 



Triplostephanus Dall, 1908 (nov.). Terebra tri$eriata Gray. 



This is Myurella Hinds, in part. 



Terebra s. 6. Lamarck, 1799. T. subulata (Linnd). 



Myurella Hinds, s. s. 1844. Terebra myuros Lam. 



Subula a. s. (Schumacher, 1817) Gray, 1847. T. dimidiata 

 (Linn6). 



Abretia H. and A. Adams, 1853. T. cerithina Lam. 



Oxymerit Dall, 1900. Terebra maculata Lam. 



This is Acus Gray, 1847, not Edwards, 1771. 



Acuminia Dall, 1908 (nov.). T. lanceata (Linne). 



Haslula H. and A. Adams, 1853. T. strigillata Lam. 



Itnpages E. A. Smith, 1873. T. cozrulescens Lam. 



Duplicaria Dall, 1908 (nov). T. duplicata Lam. 



This is Myurella Troschel, not of Hinds. 



Mazatlania Dall, 1903. T. aciculata Lam. 



Spineoterebra Sacco, 1891. T. spinulosa Doderlein. Miocene. 



Mazatlania is Euryta Adams, 1853, not of Gistel, 1848. 



1 1 use the term " pervious " technically, to denote an axis gyrate about an 

 empty space which penetrates the center of the shell internally, in contradis- 

 tinction to " umbilicate " or " perforate," which would imply a space external 

 to the inner wall of the whorls and circumscribed by them. 



