124 THE NAUTILUS. 



SUBDIVISIONS OF THE TEREBRIDJE. 



BY WILLIAM H. DALL. 



Having recently had occasion to review the genera of Terebridse, 

 it seemed that the synoptical table might have some interest for 

 students. 



Genus TEREBRA BruguiSre, 1789. 



A. Presutural sulcus present. 



Sculpture uniform at all ages, persistent, suture appressed. Sub- 

 genus STRIOTEREBRUM. 

 Shell short, small. 



1. Sculpture reticulate. Section Strioterebrum s. s. 



2. Axial sculpture emphatic, spiral obsolete. Fusoterebra. 



3. Axial sculpture obsolete, spiral emphatic. Perirhoe. 

 Shell elongate, whorls mesially constricted. 



4. Whorls nodulous at both margins. Triplostephanui. 



B. Sculpture in youth and age discrepant. Subgenus TEREBRA. 



6. Young nodulous, sulcus persistent. Section Myurella. 



6. Young nodulous, sulcus present in youth. Terebra s. 8. 

 Young axially ribbed, sulcus persistent. 



7. Adult slender, smooth. Subula. 



8. Adult small, obsoletely ribbed. Abretia. 

 Sulcus obsolete in the adult. 



9. Whorls rapidly enlarging. Oxymeris. 



C. Sulcus wholly absent. Subgenus ACUMINIA. 



10. Adult slender, smooth. Section Acuminia. 



Genus HASTULA Adams, 1853. 

 Presutural sulcus absent, suture appressed. 



A. Sculpture uniform, persistent. 



o. Shells small, slender. Hastula s. s. 



B. Sculpture discrepant. 



b. Whorls rapidly enlarging. Impages. 



Genus DUPLICARIA Ball, 1908. 

 A. Sculpture persistent, suture channeled. 

 a. Shell axially ribbed, eulcate. Duplicaria. 



