S.A. NAT., MOL. XIV. 
Mav. i.933. By Bernard C. Cotton and F. K. G odfrey. 
bridee. The species attains to 67 mm. in length by 40 in breadth^ 
and is sometimes proportionately broader, 65 x 40 (illustrated). 
The S.A. form is rarely that with the very narrow posterior end 
and the centrally compressed labrum, but the oblonga form of A. 
Adams. Over the lower fourth of the body whorl are about eight 
to twelve well marked spiral Incisions, three to five of them are 
subciistant, the rest crowded around the basal lip. Sometimes two 
broad well defined whitish bands encircle the shell, one above and 
one below the middle, each with a central dark line shaded off 
on one side. 
B. tenuissima Sowerby. -‘The Very Thin Buliaria.'’ Ov- 
.ne-oblong, subcylindrical, subpellucid, very thin; pale brown, 
varieirated with subquadrate, dull brown spots, principally ar- 
ranged in four rows; outer lip rather straight; columella margin 
white, fiat, arched, narrow; umbilicus wide. Height 23, diam. 
13 mm. One fragment, Levens Beach (Cotton). (Type locality — 
^vvan River W'.A.) Remarkable for the thinness of its semi- 
transparent texture. 
ATYIDAE. 
Shell brittle, with concealed spire; a posterior sinus, but no 
sutural slit or anal fascicle; the interior not wholly visible from 
base. Distribution — Most Seas. Fossil — Miocene. Animal with 
a quadrate head-disc, bibbed behind; eplpodial lobes large, re- 
flexed over the shell; three principal cartilaginous stomach-plates. 
Herbivorous. Sexes united. 
Haminoea T’urton 1830 (= Ila-minea Gray 1847). Thin^ 
fragile, corneous, globose, ovate or cyllndric-ovah spire sunken 
and concealed, vertex concave, imperforate or minutely perforate; 
periostracum thin; mouth as long as the shell, broadly rounded 
below, narrow above; columella concave, thin, its edge narrow!}' 
reflexed_. with a slieht fold where it joins the body of the shell; 
lip retreating above but without a distinct sinus. Type — Bulla 
hydatis Linne 1758 (British). 
H. brevis Quo}' Sc Gaunard 1833 {Bulla). PI. 1, fig. 14. 
‘The Short Haminoea.’' Rather solid, cylindrical, truncated at 
both ends; white; smooth, except for about twenty spiral stria- 
lions on the base; growth lines microscopic; vertex somewhat 
sunken but not umbilicate; mouth quite wide throughout its 
length. Height 18, diam. 10 mm. Fairly common. Yankalilla 
Bay S.A. and west to Albany W.A., beach, and dredged to 15 
fathoms. (Type locatity — King George Sound W.A.) Animal 
white, stomach containing three oblong deepl}' toothed plates. 
Shells taken by Sir J. C. A'erco at Albany beach. 10 mm. in length, 
