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Garrard states that all melanistic specimens from Queensland have a distorted base. I have melanistic specimens which were
collected by Mr. and Mrs. A. R. Bowman in the Keppel Bay area that do not have a distorted base. Garrard states that rostrate
Cypraea staphylaea descripta Iredale are never affected by melanism; a rostrate specimen of this race was recently sent to me
by Molly Bowman which was collected at North Keppel Island. and its color is not normal. The dorsum is a pale creamy color
which is slightly darker in the center, and the base is a rich deep brown which could be considered as melanistic. Molly. who
has collected for many years in this area, states that this is typical of the rostrate specimens of this race. To the best of
my knowledge, this is the only cowry affected in this way. However, I have not seen a rostrate Cypraea limacina facifer
Iredale; it is logical that it may vary in the same way as the two are closely related.
The foregoing is not intended to be critical. It is merely intended to add to the information on this subject. The most
distorted specimen that I have seen from the Yeppoon area is a large Cypraea arabica 75.4 mm in length. It was collected by
Tom Nielsen at Keppel Island and sent to me. It is a very deep blackish-brown color on the dorsum, but the lateral spots show
very clearly as the lateral area is not very melanistic.
Some of the rostrate melanistic specimens of Cypraea felina velesia Iredale from the Capricorn Islands have a diseased
appearance, and flakes of nacre are broken off which makes the shell unattractive, but those which are not flaked are
attractive. Arthur Nash and Roy Perry sent me some flaked rostrate melanistic specimens with the animal in them which I sent
to Dr. Schilder for study Schilder is quite interested in the study of aberrant specimens.
Additional localities for rostrate melanistic or specimens which are either one or the other are as follows: Rostrate Cypraea
moneta barthelemyi Bernardi have been collected in Torres Strait; I have seen a lovely rostrate Cypraea annulus annulus Linn.
which was collected by George and Ethel Young at Okinawa; Phillip Clover recently collected a pair of rostrate melanistic
Cypraea gracilis japonica Schilder in Sagami Bay, Japan and sent me one, but they are not as completely melanistic as some of
the cowries from Queensland and New Caledonia; I have several Cypraea pantherina Solander that were collected at Massawa,
Eritrea, in the Red Sea that have a uniform layer of reddish brown on the dorsum. The specimens I have which were collected
by Howard Beaver at Jidda on the opposite side of the Red Sea do not show this melanistic tendency.
I have never seen a Cypraea hesitata hesitata Iredale like the one in the picture above Garrard's article in the H.S.N. What
a prize to one who is fond of aberrations and freaks!
Cernohorsky's theory that the residue of the mineral nickel being discharged in the Bay du Monoure by a mining company might
possibly cause melanism is logical. I am certain that rusty iron can cause a form of melanistic color. However, the rust
never causes rostration to the best of my knowledge. This may be the weak point in the theory and again it may not be as
nickel could possibly produce a different reaction.
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.
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