10. S.A. XAT.. VOL. XIV. 
\'in i.MBLR, 1932. 
SOUTH AUSTRALIAN SHELLS. 
(Including descriptions of New Genera and Species). 
PART VI. 
By Bernard C. Cotton and F. K. Gom rev. 
In this part the following families are treated:- — 
Acteonulae. ()belundai\ d>trovibiiormldae and Stiliferidae. 
ACTEONIDAE, 
Shell capable of containing the entire animal; spiral, with 
projecting or depressed spire; whorls moderately numerous, inter- 
na! whorl-partitifms not absorbed; surface generally sculptured 
with spiral punctured grooves; mouth rounded below, with or 
without coluinellar folds; operculum horny, few-whorled. Distri- 
bution — World-wide. Fossil — I’rias; North America, Europe, 
South India. Animal having a well developed head-disc, bearing 
the sessile eyes, and prolonged into triangular processes behind; 
lateral cpipodial lobes not developed; proboecis not retractile. 
Sexes united in the same individual. 
Acteoa Montfort 1810 ( = Tor7iatella Lcnjmarck 1812: 
— Speo Risso 1826: Kanilla Silvertop 1838: = Myosoto 
Gray 1847). Oval, rather solid; wholly or partly grooved spiral- 
!}% with fine accremental lamellae which punctuate only the hollow 
of the groove; spire generally shorter than last whorl; protoconch 
slightly prominent, deviated, heterostrophe; sutures well marked; 
mouth elongated, rounded below, narrowed above; outer lip 
curved, slightly sinuous above, thickened inside; columella thick, 
not truncated; crossed by a strong spiral and slightly oblique 
fold; operculum horny, shaped like the mouth, few-whoricd, with 
nucleus near basal margin. Type A. iornatilis Linne (British 
Isles). Animal having the cephalic shield squared in front, pro- 
duced behind in two triangular appendages, in front of the base* 
of which the eyes arc situated. 
A, retusot Verco 1907. “The Blunt Acteon.” Oval, thin; 
shining, translucent, ycliowish-whitc; spiral incisions, six in tlie 
penultimate, forty in the body-whorl, extending, crowded ami 
fine, to the columella; axial striae, delicate, close-set, cross^ the 
incisions, which they punctuate, climb, and crenulate their sides, 
and traverse the intervening flat spiral bands; protoconch of one 
whorl, apex immersed, convex, smooth, ending abruptly in^ an 
oblique retrocurrent scar; adult whorls five, convexly sloping, 
roundly shouldered immediately below the suture ; body-whorl 
Toundly-obliqucly cylindrical; suture deeply narrowly channelled; 
