GASTEROPODA. 217 
Figures 259, 259 a, 259, three views of the animal; 259, head, 
with the proboscis protruded. 
SIGARETUS PRETENUIS, (Couthouy MS.) 
ANIMAL smaller and proportionally narrower than in S. antarcticus ; 
the mantle also is narrower, and the anterior cleft slight, making the 
front heart-shaped. Form heart-shaped, moderately convex, more 
elevated posteriorly than in front, with fine radiating lines beneath. 
Head and tentacles much as in the preceding species. Back of a dirty 
ochreous colour, longitudinally wrinkled, and having a short cinereous 
pubescence upon it. The foot is rather lighter coloured, with a 
reddish tint on the upper part; the transverse fissure is less profound 
than in the preceding species. 
Length about an inch and a quarter; breadth four-fifths of an inch. 
SHELL not examined, but seems very small, its spire being readily 
seen on the right side, at the bottom of the cavity back of the head. 
Inhabits Orange Harbour. Only a single specimen was obtained. 
Figures 260, 260 a, 260 0, three views of the animal. 
Rissoa amBicua (Gould). 
Testa minuta, albida, imperforata, ovato-subulata, costis longitudinah- 
bus exilibus ad viginti ornata, intervallis spiraliter striatis: spira 
acuta, anfractibus ad decem planulatis: apertura auriculata, antice 
subeffusa ; columella callosa, gibbosd, anticé sinuata ; labro simplict, 
incrassato. 
Pyramidella ambigua, Goutp; Proceed. Boston Soc. Nat. Hist., 11. 
118. May 1849. Expedition Shells, 60. 
SHELL minute, imperforate, dingy white, elongated, ovate-lanceolate, 
or rather subulate, about twenty delicate, longitudinal ribs on each 
whorl, the interstices marked with numerous, revolving lines: spire 
55 
