ball: MOLLUSCA and BllACHIOPODA. 247 



and projecting callosity on the inner lip in the adult, tlie name Myurella, based on 

 the Terehra myuros of Lamarck, which was designated as type a little later by 

 Herrmannsen. In 1873 E. A. Smith proposed the name Impages for Terebra 

 coerulesrens and a few similar species which were supposed (o be characterized by 

 a band of callus, extending over the body and somewhat behind the advancing 

 suture. 



The group named Euryta by Adams should doubtless be regarded as a distinct 

 genus from Terebra proper, on account of its pervious axis and abbreviated nodu- 

 lous form. The name being preoccupied for an Acaleph, the writer substituted 

 Mazadnniu in 1900. Spineoterebra Sacco, is proposed for a shell very similar to 

 Mazatlania, but with a callous pillar, with a different canal and an impervious axis. 

 The canal is so little indented tiiat the siphonal fasciole is almost obsolete, and the 

 keel, which usually marginates its posterior edge, is represented only by a slightly 

 raised line of junction. Being doubtless the .incestor of Mazatlania and the name 

 prior, it will take generic ))reccdence, while Mazatlania will form a subdivision 

 under it as a subgenus. Wlietlier Cossmann's Noditerebra comes under Spineo- 

 terebra or is a variant of Strioterebrum is not clear from the description and 

 rather obscure figure, and I have not been able to examine a specimen. 



Having gone over the entire collection of recent Terebra in the National Mu- 

 seum, and tabulated the characters of each species, I have formulated the follow- 

 ing arrangement. It should be premised, however, that apparently Hinds was 

 quite right in concluding tliat so far as the shell characters are concerned, no rig- 

 orous lines of subdivision can be drawn within the genus, though groups which 

 are for the great majority of the species perfectly recognizable may easily be 

 segregated. 



Tlic larval shell throughout the group is the same, except in numher of whorls. 

 It is blunt, glassy, smooth, and forms a shorter or longer subcylindrical spire. It 

 is usually dark-colored. The nepionic shell may agree in sculpture with the 

 adult portion, or may be entirely different, its sculpture gradually becoming modi- 

 fied with growth. So far as reported the operculum is uniformly suhaunular, 

 ovoid, narrow with a terminal nucleus. 



The old genus Terebra is now admitted to be necessarily divided into four 

 distinct genera as follows : 



Terehridae. 



Tkrebra Bruguicre. Radula edentulous, tiie proboscis forming a voluminous, 

 muscular, evertil)le sac, in which the prey may be enfolded and its juices squeezed 

 out and absorbed. The presence of a poison gland may be explained by suppos- 

 ing the secretion to paralyse the living prey when taken into the sac. Eves 

 terminal on very short small tentacles, and a long slender verge without append- 

 ages, are present. Type Terebra subuhtta (Liinid). 



lUsTULA. Adams. Radula with Toxoglossate teeth as in Conns, pierced for 

 the secretion of a poison gland ; eyes and tentacles present. Type Terebra strigil- 

 lata Lamarck, not Cimelin. 



