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Land snail
Caroline Is.:
Recently Mr. C. N. Cate presented me two walkeri from Moen Is. in the Truk Is. (coll. Schilder No. 17135 and 17136); they
formerly belonged to a series of fifteen similar shells dredged by R. Willis in the harbour in January 1962. These two shells
are "pellucid" like the dead glossy cowries dredged in Honolulu harbour, and exhibit a similar white chalk in the aperture:
there, the conditions of preservation in the harbour of Moen Is. must be about equal to those in Honolulu. The specimens
undoubtedly belong to walkeri (surabajensis) and not to bregeriana: the discovery of this far-off population of walkeri in
the central Caroline Is. is not very surprising, as other typically Malayan cowry species also spread to western Micronesia,
e.g. Erronea ovum Gmelin and E. onyx Linnaeus to Palau and Guam respectively.
Northern Melanesia:
Mrs. K. Matcott of Mooloolaba, Queensland informed me by letter in March 1963, that she possesses a "surabajensis" from New
Britain; as I have never examined the shell personally, the reliability of this indication seems to need confirmation.
Fiji:
Mr. W. O. Cernohorsky has quoted walkeri bregeriana from New Caledonia and Fiji, in his recently published Catalogue of
Living Cypraeidae (Frankfurt-Main 1963). In fact, since 1962 at least eight bregeriana have been collected in Fiji, all off
the West Coast (Nadi and Momi) facing towards the chief habitat of bregeriana, New Caledonia; especially Mr. A. Jennings has
dredged, at the islands Wading, Akuilau, and Namotu (20 miles off Nadi) several dead and living specimens, one oliviform
shell included of which I could examine the radula (Mr. Cernohorsky presented me a shell from Momi, coll. Schilder No. 17154,
which is 17 mm. long). All specimens show the typical orange base, often darker brown in the center of the inner lip, and the
peculiar white specks on base and margins, but they are much smaller (16 to 21 mm., mean 18 mm.) than typical bregeriana from
New Caledonia (20 to 33 mm., mean 25 mm.). These shells look like a population displaced far from its original habitat in New
Caledonia, where bregeriana is less rare, to an area with less favorable environments, as it is in the two dwarf Erosaria
ocellata Linnaeus from Tjilanat Eureun, South West Java widely separated from their Indian relations (see 1938, Prodrome, p.
138).
South East New Guinea:
If bregeriana could spread from New Caledonia to Fiji, it probably also could spread to North West: therefore I now do not
doubt its occurrence in Joanett Is., Louisiade Archipelago, from which locality Smith (1888, Journ. de Conchyl. 36:313) has
described three bregeriana of 21 to 22 mm.
The indications of habitat: Persian Gulf, Red Sea, Victoria, New Zealand, and Tahiti evidently are erroneous.
The appended map clearly shows the advancement of our knowledge concerning the distribution of Erronea walkeri since World
War II. It should encourage malacologists to further research.
Having a special interest in mollusks of the West African coastline, I have inquired as to why shells from that area are
often so difficult to obtain. The above pictures graphically show the reason.
The natives of the area seem to have a real passion for the use of sea shells as personal decorations, many collectors'
treasures being used as ornaments.
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.
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