250 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



Subgenus Impages Smith, 1873. 



Shell larger with whorls flat aud rapidly enlarging ; sculpture of young and 

 old discrepant. Young, faintly axially ribbed, the suture appressed, with no 

 sulcus or baud ; the adult smooth, a thin wash of callus on the body, extending 

 over the whofl beliiud the line of the following suture ; inner lip not raised, the 

 aperture with no posterior channel or anterior canal, but a deep siphonal sulcus, 

 the pillar with one more or less hidden keel. Type Terebra coerulescem Lamarck. 



The baud of enamel behind the suture is not very conspicuous and may not be 

 of much systematic value; the other characters, however, seem to give it a 

 certain value. 



DUPLICARIA Ball. 



DcPLiCARiA Dall, Nautilus, March, 1908, p. 124. 



Shell small, acute, similarly sculptured throughout, witli sharp, regular, 

 numerous axial ribs crossing the flat whorls aud divided by a conspicuous spiral 

 sulcus ; suture distinctly channelled ; pillar with a single keel, the columellar 

 lip not callous or raised, the canal obsolete, the aperture with no posterior 

 channel. Type Terebra duplicata Lamarck. 



Tills is Myurella Troscliel, not Hinds. The anatomical characters have already 

 been mentioned and forbid its consolidation with the other genera. It is the 

 only group in the family with a channelled suture. 



SPINEOTEREBRA Sacco. . 



Subgenus Spineoterebua Sacco, ISOl, s. s. 



Shell rather elongate, with knobby axial sculpture, no spiral sculpture, an 

 impervious axis, and a markedly callous pillar lip. Type Terebra spinulosa 

 Doderlein, Tortonian. The siphonal fasciole is nearly obsolete. 



Subgenus Mazatlania Dall, 1900. 



Shell shorter, buccinoid, thin, with sparse knobbed axial ribbing, spiral sculp- 

 ture cons|)iouous toward the canal; the pillar gyrate, the axis pervious, the pillar 

 lip bare, the siphonal fasciole well developed. Type Terebra aciculata Lamarck. 



Mazatlania is Euryta Adams, 1853, not of Gistel, 1848. It appears to be a 

 descendant of Spineoterebra, which is intermediate between Slriotcrebrum aud 

 Mazatlania. The soft parts of both are unknown. 



Terebra (Strioterebrum) panamensis Dall, n. sp. 



IMato 5, Qjjure 10. 



Shell small, acute, twclvc-whorlcd, with rather prominent sculpture and a 

 generally brownish tint; nucleus eroded in all the specimens; subsequent whorls 



