338 DR. H. LYSTER JAMESON ON 
Three of these pearls were decalcified, and one of them, Preparation 
LXXXVIA, was also sectioned. All showed centres of the same 
class as those of the pearls in Dr. Kelaart’s collection—that is to 
say, central cavities containing irregular conchyolin-like strands 
and a few granules. Two of these pearls were fair spherical 
pearls, about 3mm. in diameter, which would have ranked as 
‘“‘fine” pearls or ‘“* cyst-pearls,” b ae for blemished surfaces. The 
third was a multiple pearl, secondarily attached to the shell, and 
showed, by the presence of distinct traces of hypostracum in its 
substance, that it bad arisen in a muscular part. 
E. Collection of Pearls given to me by Mr. Max Mayer. 
In April 1911, Mr. Max Mayer, of Hatton Garden, London, 
and Paris, denies in precious stones, most generously gave 
me for the purposes of my work a number of pearls, mostly 
of the baroque and seed class (though some could better be de- 
scribed as pearls that would have ranked as small “ fine” pearls, 
but for defects of shape, colour, or surface). These included 
a sample which, after eliminating a number of pearls that, 
from their colour and other qualities, Mr. Mayer considered 
were derived respectively from Australia and Panama (these will 
be dealt with in another paper), left a mixed lot of 115 pearls, 
most of which showed more or less of the characteristic and 
indescribable creamy colour which is distinctive of the pearls 
of Margaritifera vulgaris. Myr. Mayer had no hesitation in 
saying that the majority of these were almost certainly Ceylon 
pearls, though he emphasized the fact that it is not often that 
pearls reach the European markets accompanied by “ certificates 
of birth,” and that the sources of these specimens could only be 
judged from their respective characters. 
These 115 pearls were decalcified and eight of them were 
sectioned, and several others were dissected to expose the 
nature of the ‘“‘ nucleus” or pseudo-nucleus. 
Of this collection not one had a nucleus that could be identified 
as a Cestode, or indeed as any parasitic worm. Sixty of them had 
spheerocrystal-like pseudo-nuclei composed of columnar repair- 
substance, sometimes simple, sometimes stratified, sometimes 
interstratified with other repair-substances. In some cases a few 
granules could be detected in the centre, in others nothing of the 
kind could be made out. These pseudo-nuclei were generally less 
transparent than the residue of the pearl, often almost opaque 
but in every case their nature was obvious. Forty-two pearls 
were of the kind described from Dr. Kelaart’s specimens in the 
British Museum, 7. e. they had either no obvious nuclei or their 
centres contained cavities in which were a few strands of 
conchyolin-like substance. Six others were of the same class, but 
contained some refractive granular matter. One double pearl 
showed a columnar pseudo-nucleus in one constituent and a 
centre of the “Kelaart” type in the other, while another, 
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