GASTEROPODA. lll 
Truncatella porrecta, Goutp ; Proceed. Boston Soc. Nat. Hist., ii. 
208. March 1847. Expedition Shells, 40. 
SHELL small, very slender, subcylindrical, rather thin, decollated 
at apex, dirty white, remaining whorls four, unusually convex and 
separated by a profound suture, barred with about sixteen delicate, 
sharp, humble ribs, the intervening spaces, when viewed by a strong 
magnifier, minutely striated lengthwise. Aperture rounded-lunate, 
stretching to some distance beyond the penultimate whorl ; lip conti- 
nuous, broadly expanded on the outer side, erect on the columellar 
side, leaving the penultimate whorl at some distance. The opercu- 
lum is bony, eccentric, and its elements rise into sharp, elevated 
lamine, 
Length one-fourth of an inch; diameter three-fortieths of an inch. 
Inhabits Tahiti. 
The distinguishing marks of this shell are its slender form, its 
sculpture, the unusually rounded whorls, and the great protrusion of 
the last whorl. Only one specimen was examined. 
Figure 127, front view of the shell; 127a, side view of the last 
whorl; 1278, aperture, with the operculum, all enlarged ; 127, natu- 
ral size. 
TRUNCATELLA ROSTRATA (Gould). 
Testa parva, conico-cylindracea, nitida, decollata, incarnata, oblique 
clathrata ; clathris ad duodecim robustis: spira anfractibus quinque 
convexiusculis: apertura parva, oblique ovata; peristomate continuo, 
crasso, albido, duplici, reflexo. 
Truncatella rostrata, Goutp; Proceed. Boston Soc. Nat. Hist., 11. 
209. June 1847. Expedition Shells, 40. 
SHELL small, elongated, conical, flesh-coloured, barred somewhat 
obliquely with about twelve stout bars on each whorl, which disap- 
pear before reaching the base. Whorls about five, slightly convex, 
the apex detruncate. Aperture small, obliquely ovate; lip large, 
