DALL: MOLLUSCA AND BRACHIOPODA. 247 
and projecting callosity on the inner lip in the adult, the name Myurella, based on 
the Zerebra myuros of Lamarck, which was designated as type a little later by 
Herrmannsen. In 1873 E. A. Smith proposed the name Impages for Zerebra 
coerulescens aud a few similar species which were supposed to 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 preoccupicd for an Acaleph, the writer substituted 
Mazatlania 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 that 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 ancestor of Mazatlania and the name 
prior, it will take generic precedence, while Mazatlania will form a subdivision 
under it as a subgenus. Whether 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 that 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. 
The larval shell throughout the group is the same, except in number 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 subannular, 
ovoid, narrow with a terminal nucleus. 
The old genus Terebra is now admitted to be necessarily divided into four 
distinct genera as follows: 
Terebridae. 
Treresra Bruguiére. Radula edentulous, the proboscis forming a voluminous, 
muscular, evertible 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. Eyes 
terminal on very short small tentacles, and a long slender verge without append- 
ages, are present. Type Terebra subulata (Linné). 
Hasruza Adams. Radula with Toxoglossate teeth as in Conus, pierced for 
the secretion of a poison gland ; eyes and tentacles present. Type Zeredra strigil- 
lata Lamarck, not Gmelin. 
