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Murex borneous
Let me prove this accusation by discussing the variation in size of Cypraea tigris in Fiji. In The Cowry (1:3, p. 43, 1962)
F. A. Schilder has stated the average length of tigris from Fiji and Tonga as 76 mm. In The Cowry (1:5, p. 74, 1963) W.O.
Cernohorsky writes: "Every Fijian collector has a specimen of tigris from 105 mm to 110 mm...I have seen nearly 25 specimens
of tigris approaching 110 mm... From personal observations and measurements I place the mean length of C. tigris from Fiji as
about 90 mm." Let us see how this difference can be explained, and which indication is correct.
Apparently W.O. Cernohorsky fears that research workers may be led astray by only using shells from a single locality of a
region and he tells us that with some populations in Fiji, all shells are "dwarf" size. In others (especially Vatia Wharf)
all shells are "giant" size. As Mr. Cernohorsky has collected for us in a most generous way with thousands of Cypraeidae
(mostly with the animal within) from many localities all over Fiji, we base our research of Fijian shells mostly on the
specimens collected by him. In addition, Mr. Cernohorsky often provides us with the results of his own measurements of other
specimens. He told us that his maximum tigris from Vatia Wharf is 92 mm long.
We measure each shell with calipers in tenths of millimeters and get our means from each series of each locality. The
following table indicates
(1) the number of specimens,
(2) the exact locality,
(3) the length (in classes of 5 mm: 65 = 63 - 67, 70 = 68 - 72, etc.), and
(4) the mean of the length in mm.
The mean of the 7 means of population is 78, as well as the mean of all 93 specimens coming from these localities. The mean
indicated in The Cowry (1:3) was 76 instead of 78, as other sources were used there too, shells from museums, from the study
of Dr. A. Kay in The Veliger (4:1, p. 36, 1961) and shells from Tonga. But the mean of tigris from Fiji can never be 90 mm as
W.O. Cernohorsky suggested
The last two lines of the table refer to the 24 females and 33 males examined from all Fijian localities (except Vatulele
Is., where only dead shells have been collected): therefore the mean of the sum of 57 live specimens is a little higher (79
mm) than that of all 93 specimens. The difference between the average size of females (81 mm) and males (78 mm) agrees with
that observed in most other species of Cypraeidae: the average size of males is only about nine tenths of that of the females
(see The Cowry 1:4, p. 50, 1962).
The average length of shells can be approximately estimated by halving the sum of the minimum and the maximum known. As our
tigris from Fiji vary from 60 to 92 mm, the estimated mean is 76 mm, which figure rather approaches the mean size 78 mm
calculated above. This rule, however, can only be adopted for shells coming from a restricted area or at least belonging to
the same geographical race. It does not fit the tigris coming from the whole Indo-Pacific: the mean of the two extremes (44
mm measured by F.A. Schilder, 1930, in coll. Vayssière in Marseilles, and 147 mm mentioned by A. Kay, 1961) is 95 mm; it is a
far too large figure, as it is influenced by the Philippines local race schilderiana Cate (80-147 mm, estimated mean 114 mm),
while typical tigris from the vast area from East Africa to Polynesia are much smaller (44-112mm estimated mean 78 mm). The
latter figure agrees with the calculated mean of the specimens from Fiji.
After an hour of surface decompression, our meter was at a safe reading. Over the side we went, each hoping to find something
better than the others. We were working on a sand and mud bottom with a few scattered rocks. On the bottom, we found a
fragile type of purple coral that crumbled when picked up. Also, a greenish-white type of coral was found that resembled
oatmeal when it was broken up. In this rubble and under the rocks, we found all of the shells collected. On the last dive,
some of this rubble was brought to the surface in bags to be sorted through at our leisure. It is just as interesting to go
through this rubble as it is to dive for the shells. The second dive was not as long as the first because everyone was
working harder. Also, each diver was not sure his shells would be in his glass jar in the boat if he came up last. We are an
honest group but we are collectors. After everyone was back in the boat, a count of the shells taken was made. A total of 28
Cypraea gaskoini, 3 C. chinensis, 2 C. rashleighana, 1 Cymatium clandestina, 7 Vitularia, 3 Cymatium echo, 4 Conus pertusus
and a wide variety of Mitra and other Conus species were in our collecting jars.
So ended this, a truly record day!
John H. Roberts, Jr. offers the following Helpful Hint:
I often find myself deluged with questions regarding methods I employ in cleaning shells. My latest method, and most
successful, is the use of Pineoleum[tm], a household disinfectant. I use Pineoleum[tm] full strength and soak my shells (all
types) for several days before removing for cleaning. There is no etching or discoloration of the shell soaked in this
solution. For Cypraea, this is the finest yet. In most cleaning preparations, there is corrosive acid action. However, with
the oil base in Pineoleum[tm], a thin film of oil covers the shell, preventing any etching or discoloration. When the
interior of the shell is cleaned out, just wipe the external surface with a dry cloth and the Cypraea is just as it was when
found. There is no need for livening up a shell's coloring by use of silicon grease. This, I am told, is employed by some of
our Honolulu collectors.
L. chiragra, etc., or the violet spots of Cypraea chinensis will fade through boiling. Especially if the shells were not
washed and rinsed before, so that the boiling water does not contains salt, mucus or decomposed animal matter. So better
avoid boiling these shells. Some bivalves, especially such which come from muddy bottom, may change their colours through
boiling. Some Aplysiidae, who have a delicate, internal shell, shrivel and contract through boiling and this usually results
in a crushed shell. But cone shells, Mitra, Oliva, Terebra and most Cypraea can be boiled without harm to the colour.]
It is a pity that collectors nowadays strive only to possess the largest shells of each species and thus neglect the small
ones. Formerly, collectors would boast that they possessed both the largest end the smallest shells of a species. You will
see, for instance, that a dwarf Cypraea tigris of about 40 mm compared to one of about 150 mm is a surprising contrast worthy
to be exhibited in any collection.
The reason for my complaint is that by this preference for giants, scientific research is handicapped in defining the mean
size of a species from a certain region or from all parts of the world where the species occurs. As most local collectors
keep the rare, large shells for their own collections, the abundant medium sized and the rare, small shells are not
preserved. Then the local collectors pretend that the scientist is wrong when he indicates smaller figures for the average
size.
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