ACTAONID. I19g 
shell, which is limpet-shaped, with a posterior sub-spiral apex, and a 
fimbriated dorsal keel ; nucleus minute, dextrally spiral. 
C. australis, Quoy, Voy. Astrolabe, p. 394, pl. 29, f. 9-16. Shell 
thin, hyaline, transversely sulcated ; apex obliquely inclined ; keel undu- 
lated ; spire obtuse, on the right towards the whorls four elongated 
oval apertures ; swimming foot extended, quadrilateral (Quoy.) 
Sub-Order—Opisthobranchiata. 
Gills exposed or slightly covered, behind the heart ; hermaphrodite, 
mostly carnivorous ; gelatinous, full of sea water. Shell when present 
enclosed in the folds of the mantle; abdomen rudimentary, not spirally 
developed in the adult, or protected by a shell; larva shell-bearing, 
and furnished with deciduous cephalic fins. 
DIVISION—TECTIBRANCHIATA. 
Gill forming a tuft or plume on the side, towards the hind part of 
the body, under a fold of the mantle, and usually protected by a shell. 
Both adult and larva shell-bearing. Foot elongate, formed for walking. 
Marine. 
FAMILY—ACTAONIDA. 
Teeth, central none, lateral numerous, uncinated, in a diverging 
cross series. Head depressed, forming a quadrate disc, bi-lobed in 
front, with broad, posterior, tentacular lobes ; eyes sessile on the middle . 
of the head. Mantle included within the shell ; branchial plume single. 
Foot oblong, truncate in front, obtuse behind. Operculum horny, 
linear, transverse. Shell solid, involute, with the columella plicate or 
spirally twisted. 
Genus, BUCCINULUS—Plancus. 
Ovate, with a conical many-whorled spire; mouth long, narrow, 
rounded in front ; columella with two spiral folds ; operculum horny, 
elliptical, lamellar. 
B. kirki, Hutton, CMM, p. 51. Whorls six, finely and rather 
distantly spirally grooved, those on the centre of the whorls rather 
farther apart ; columella with one double fold ; white. 
Length, 8 ; breadth, °3. 
Omaha. 
B. albus, Hutton, CAL W., p. 51. Whorls seven, rather deeply 
equi-distantly spirally grooved, and lightly transversely striated ; colu- 
mella with a broad double anterior fold, and a smaller posterior one ; 
white. 
Ieneth, <9 > breadth, +15: 
Auckland. 
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