147 . 
-S.A NAT., VQL. 'XIV. 
August 31st, 1933. /iy Hrrnard C. Cotton r.iut F. K. Godfrey. 
has no appendix, the ribs are more valid and do not so 
soon become obsolete, and it is not found in such shallow water, 
ddie absence of the aj'ipendix may be only an accidental circum- 
stance, and the shallower water in which the \A'^estcrn Australian 
species lives may account for the other differences, and that this 
is only a local variety. One individual from Geographe Bay, 
tneasuring 4 x .5 mm., has the apical end complete. 
SIPHONODENTALIIDAE 
{—Siphonopoda Sars: — GadtUnae Stoliezka: := Siphonopodidae 
Simroth). Shell small and generally smooth, often contracted 
towards the mouth. Distribution — All seas, from the tidal zone 
to the abyssal depths. Animal having the foot cither expanded 
■distally in a symmetrical disc with crenate continuous edge, with 
■or without a median finger-like projection, or simple and vermi- 
form, without lateral processes. Characteristics which differ 
from Dentaliidae are referred to under class ScapJiopoda, 
Cadulus Philippi 1844, Small, more or less arcuate, gener- 
ally swollen, or with an inflated bulging area in the middle por- 
tion of the shell or near the anterior aperture; white; without 
any sculpture; aperture more or less contracted and usually very 
■obli(|ue; apical aperture proportionately quite large as compared 
with that of Dentalium, and either simple or cut by two or four 
slits; section round or flattened; occasionally an internal circular 
rib is developed just within the apical orifice. Type — Dentalkim 
■ovulum Philippi (Alediterranean). The genus is represented in 
all depths, rhe mollusc lives in sandy and muddy stations and 
often in great Individual quantity. Species not usually very wide- 
ly distributed but certain excej’tions are notable. The idea of 
variation of individual species is exaggerated by breakage of the 
ends causing the shortened specimens to appear more inflated. 
Texture of shells is vitreous and more or less translucent; tlierc 
may be circular deposits of shelly material, causing alternate 
rings of more or less translucency which are not, however, specific 
characters, but appear to be wholly individual and possibly path- 
ologic. The concave side is commonly accepted as dorsal, and 
the convex ventral. The Important specific characters of the 
C'aduli are the slits aitd lobes about the edge of the apical orifice, 
the general shape of the shell, the ratio of length to breadth, the 
localised or general type of swelling, the compression of the shell, 
■the obliquity of the aperture, and, lastly, the size. A good way 
to identify material is to examine first the apical characters in 
order to place the shells in their proper subgeneric groups; then 
:seek among figured species of similar size for those with median 
