298 DR. H. LYSTER JAMESON ON 
Most of these slides were preparations showing the parasitic 
Cestodes in the tissues of the oyster, but there were also a number 
of preparations of pearls, sectioned in sitw in the tissues, showing 
in all about 25 pearls, 21 of which showed their nuclei more or 
less distinctly. The nuclei of these pearls were of very different 
characters, but in no case could I identify a Cestode larva in the 
centre of a pearl. 
(vi.) Three Specimens from the Persian Gulf. 
In September 1903, Mr. J. Caleott Gaskin, Assistant Political 
Agent at Bahrein, Persian Gulf, sent me 32 specimens of 
Margaritifera vulgaris from Bahrein preserved in alcohol. Out 
of 20 of these that I opened, 3 contained pearls, which, from their 
position, could obviously be classified as “* eyst-pearls ” (Herdman). 
‘wo contained a single pearl each, that in the first being about 
2°5 mm. in diameter, situate in ye left mantle-lobe, above the 
anterior end of the attachment of the gills | Preparation LXIV Al, 
that in the second [ Preparation LXIV B] being about 1 mm. in 
diameter and situate in the body-wall over the stomach. The 
third specimen had two small pearls, about 2 mm. apart, in the 
wall of the visceral mass, away from all muscle-impressions 
[|LXTV coc], All these pearls were decalcitied in situ in the tissues 
and sectioned. Their centres are described below. 
In addition to the above the following pearls were decalcified 
and examined. More detailed particulars are given under the 
descriptions of the centres of individual pearls, given below :— 
(vu.) Dry unlabelled pearls, probably from Ceylon, in the 
British Museum, three examples were decalcified. 
(vill.) Mixed lot of pearls; given to me by Mr. Max Mayer, 
mostly from Margaritifera vulgaris ; 115 were decalcified, of these 
8 were sectioned, 
(ix.) A collection of pearls from the last Ceylon pearl fishery, 
given to me by Mr. E. Hopkins. Fifteen were decalcified, 
and four of these were sectioned. 
(x.) A collection of pearl-oysters, with pearls i sitw, from the 
Gulf of Kutch; these are referred to above. Up to the time of 
writing, 18 pearls from these specimens have been decalcified, 
and 13 of them sectioned. 
(xi.) Two pearls from Margaritifera vulgaris, from the 
Mediterranean, given to me by Professor Raphael Dubois. 
(xi1.) Five weotle from Margaritifera vulgaris, from New 
Caledonia, given to me by Professor L. G. Seurat. 
(xi.) A pearl from Margaritifera vulgaris, from Madagascar, 
given to me by Professor Seurat. 
(xiv.) Two pearls from Margaritifera vulgaris, from Papua, 
from the Imperial Institute. 
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