
The EGG CAPSULE or tun SOUTHERN AUSTRALIAN 
BALER SHELL MELO MILTONIS GRAY 
Ry BERNARD C. COTTON, Concuorostsr, Sours AvsrratiaAn Museum. 
‘nine has beer little regeareh in Australia and indeed in the world, on molluscan 
eggs aidege capsules. In South Australia many kinds are found washed up on the 
beach i considerable quantity between the months September and December, and 
althoueh the speeifie identities of some have been decided, many are still uncertain. 
It 1s desirable that any definite records and identification be published, 
In this publication Vol. VI, No, 1, Nuvember 30. 1987, p. 101, a deseription of 
the ege vapsule of a Western Australian specimen of Melo maltonis was given. The 
protocanehs in the eapsule were well developed and apparently on the point of 
hatching. averaging 26 mm, in leneth, We have now a reeord of a Sonth Australian 
specimen, in November, 1943, Mr. Albert J, Blumson wrote detailing observations 
made through lis glass-hottomed boat.and supplying a specimen of the Baler Shell 
and its capsule taken in South Australia, 
The specimen forwarded is dried and now measures in length 70 mm. and 
width 70 mm,, but according to a photograph taken immediately after the specimen 
was secured the dimeasions would be approximately in length 200 mm, and in 
width 130 mm. atthe widest part vear the base, The capsule was taken in fourteen 
feet of water off Cape Vivonne, near Ceduna, West Coast of South Australia. 
When firgt seen in the Water it was atlached to a fragment of limestone and was in 
size and shape very much like a pineapple, The surface shone like a piece of opal 
with iridescent, bright, changing colours. The general surface consisted of mumer- 
wus individual chambers with a space of about 6 mm. between. In eonsisteney it 
was ahovt as tough and pliatile ‘as a new motor tyre’? The animal responsible 
for the capsule is a perfect specimen measuring in leneth 250 mm, and width 140 
mink, dud is mature, being comparatively thickened towards the outer lip. A 
further Baler was observed in the process of forming a capsule. When taken hy 
Mr. Ghonson the basal layer had already been deposited in the form of a disk on 
(he upper avurface of a e¢mglumeradion of dead Port Lineoln ovster shells. The 
Baler clung to the oysters so effectively that they could not be separated by hand. 
The specimen was placed in a wet bag for later examination. The Baler clung to 
the oysters for ten hours, and when it tinally relinquished its hold it was observed 
that the bottom Iayer of ten sections of the egz capsule had been formed, 
The epg capsules are normally attached to some hard and fixed surface, but 
When accidentally detached they float base downwards and their centre of gravity 
Mist be at such a point as to ensure this, for whatever way they are placed in the 
water they roll over into theiy normally vertical position. 
The complete capsule, now thoveaghly dried, has shrunk and the protoeonchs 
have probably disinteyrated as they cannot be seen within the eayities. In all 
probability the capsule had only just been completed and little development of the 
embryonie shell had talcen place. 
There are apparently abont ten sections, or individual eavities, situated at the 
circumference of cach of the ten layers, giving a possible one hundred cavities 
and proforonchs, thouch a number of the apical cavities may not contain embryos. 
Compared with the Western Australian specimen, which measured im length 
169 mm, and width 75 mm. our specimen appears bigger. However the Western 
Australian specimen has evidently shrunk in the preservative, Again the number 
