243 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
ignored in the index to his volume. It is uncertain which use of Cylindrella 
was prior, Swainson’s or Pfeiffer’s; the latter having also used the name (for 
landshells of the genus Urocoptis Beck) in 1840. The presumption, however, is 
in Pfeiffer's favor, in comparison with Swainson. It would be a pity to resurrect 
a name so well known in so unfamiliar a connection. Cylichnus Burmeister is a 
barbarism, and cannot be derived by any recognized rule of orthography from the 
Greek xvAcyyn, from which we might obtain Cylichnes or Cylichnium, as well as 
Cylichna. The latter might thus be plausibly held until it be shown that Cylich- 
nus is a masculine form of it. I do not like to use Mnestia for the genus, 
thinking it highly improbable that the colored species for which that name was 
proposed are identical with the group typified by C. cylindracea Pennant. The 
next name in order of date is Cylichnella Gabb, the shell of which differs from 
Cylichna by having two distinct plaits on the pillar instead of one, and since this 
has been recognized by Gabb, Pilsbry, and others as a distinction of rank not 
greater than subgeneric Cylichnella will become the generic name with the species 
formerly grouped under Cylichna now forming a subgenus with the name of 
Bullinella Newton. It is of course understood that with the general knowledge 
of the anatomy some revision will undoubtedly be called for. 
The genus may be subdivided as follows: 
A. SHELL UNICOLORATE, CYLINDRIC. 
CyLicHNELLA Gabb, s. s., type C. didentata Orb. Pillar with two distinct 
plaits. 
BuuiineLia Newton, type C. cylindracea Pennant. Pillar with a single plait. 
Cyticunium Dall, xov., type Utriculus domitus Dall. Pillar simple, aperture. 
ample in front. 
B. SHELL VERSICOLORED, SUBOVATE. 
Myestia H. and A. Adams, type, C. marmorata Adams. 
Cylichnella (Bullinella) inca Datt, n. sp. 
Plate 11, figure 3. 
Shell small, white, with a pale yellowish periostracum (mostly eroded), the 
aperture as long as the shell; spire entirely and deeply immersed, leaving only a 
small deep cylindrical perforation at the apex; summit of the whorls rather evenly 
rounded, except where slightly indented by the more pronounced incremental 
irregularities ; sides nearly parallel, the posterior end, if anything, with a slightly 
greater diameter ; surface smooth (where not eroded) except for lines of growth; 
middle of the shell a trifle constricted ; body with a light wash of callus; outer 
lip thin, sharp; pillar a little twisted with a faint trace of a revolving ridge upon 
it; anterior end rounded. Jon., 6; max. diam., 2.5. mm. 
U.S. 8S. “Albatross,” station 3392, off the Gulf of Panama, in 1270 fathoms, 
hard bottom, temperature 369.4 N. U.S. Nat. Mus., 123,080. 
