456 Mr. W. T. Blanford on the Classification of — 
by its sculpture, which is distinct in general from that of any 
other of the Cyclostomacea, except Diplommatina, and in the 
absence of any tendency to coloured zigzag markings—a cha- 
racter which may not appear of much value at first, but which 
is nevertheless singularly constant throughout the genera Cyclo- 
phorus, Pterocyclos, Opisthoporus, Cyclotus, &e.—in fact, nearly 
all the Cyclophorine. The animal is similar to that. of Pupina, 
having short, black tentacles, and differs in no essential point 
from Cyclophorus. 
The large addition to the number of species renders it possible 
to define more exactly the generic characters ; and the following 
may be suggested :— 
Testa perforata v. umbilicata, conica, turbinata, globosa vel de- 
pressa, unicolor, albido- y. succineo-cornea, rarius rubella. Anfractus 
convexi, ultimus ad latus tumidus (spatio inflato sculptura confertiore 
plerumque ornato), deinde prope aperturam constrictus, tubulo su- 
turali externo, pone stricturam oriente, antice in anfractu aperto, 
cum spatio inflato longitudine concordante, postice clauso munitus. 
Peristoma circulare, plerumque incrassatum vel reflexum, Operculum 
corneum (rare subtestaceum?), multispirum, nucleo centrali interno 
prominente seepe munitum. 
In the ‘ Ann. & Mag. Nat. Hist.’ for March 1859, Mr. Benson 
suggested the division of the genus into a typical section and 
two subgenera, which he named Charaz and Dioryz, distinguish- 
ing the three sections by the characters of the constriction, the 
typical group embracing such species as have “the last whorl 
constricted somewhat remotely behind the aperture, tumid on 
both sides of the constriction.” In the section Charaz, the 
constriction is “ broad, contiguous to the aperture, and divided 
more or less remotely from it, across the whorl, by a ridge, 
which is hollow internally.” In Dioryz the constriction is 
“narrow and immediately behind the aperture.” 
This distinction appeared at the time to be good, with the 
exception that one of the species referred to Dioryax (A. crenu- 
latus, Bens.) was more closely allied in most of its characters to 
a form of Charaz than to the members of its own section. But 
there was evidently, after the removal of this species, a much 
closer alliance between Charax and the typical group than be- 
tween either of those types and Dioryz. To this Mr. Benson 
referred in his paper, and also to the fact that the Western 
Himalayan species, A. strangulatus, Hutt., showed a tendency to 
a passage from Charaz to the typical section. Since the publi- 
cation of Mr. Benson’s observations, some other species have 
been discovered, especially A. Theobaldi, W. Blanf., and A. poly- 
gonoma, W. Blanf., which are also intermediate in the characters 
eS 
of the constriction ; and it may be doubted whether the form of | 
