344 DR. H. LYSTER JAMESON ON 
decalcified and mounted entire in Canada Balsam. In none of 
these could I find Cestode nuclei. 
The example mounted as a slide was a pearl about 2 mm. in 
diameter, of oval shape, from the Isle of Pines. It had two 
pseudo-nuclei, side by side, both composed of columnar substance, 
concentrically laminated. One measured *5 mm., the other 
‘3mm. This pearl was subsequently sectioned, and no foreign 
matter could be detected in the nuclei. I decalcified and examined 
the other four pearls. The characters of three of them were 
nearest to those of the pearls in Dr, Kelaart’s collection in the 
British Museum described above, but one had several centres, 
which were surrounded by columnar substance. The fourth had 
a little brown body about -2 mm. in diameter, which sections 
showed to be composed of unrecognisable granular matter 
surrounded hyamorphous substance, No Cestode characters could 
be identified in it. 
M. Seurat also sent me five slides, with sections of pearls from 
M. vulgaris from New Caledonia, which had been mounted in paraftin 
wax, but had not been stained or made into finished preparations. 
T stained and completed these, and found that they comprised 
about seven pearls, in all of which, so far as could be determined 
(for the series were not complete), the pseudo-nuclei were either 
simple cavities containing a few granules or strands of conchyolin- 
like matter, or masses of concentrically deposited, stratified 
columnar substance. There was no trace of anything that I could 
accept as a Cestode. 
M. Seurat stated (37), p. 24, that these pearls had for nuclei 
Cestode larve, but I am unable to confirm this. In a recent 
letter he has informed me that this assertion was based on the 
appearance of the nucleus of a decalcified pearl, which was not, 
apparently, examined in section. 
J. Pearl from M. vulgaris from Nossi-bé, Madagascar. 
M. Seurat also sent me an unmounted slide with sections of a 
pearl from this species from Nossi-Be. The centre of this pearl 
was a mass of concentrically deposited columnar substance, 
0-35 mm. in diameter, containing a cavity about 0-l mm. in 
diameter. 
K. Pearls from the Lapi Shell (M. vulgaris), from the 
Trobriand Islands, Papua. 
Prof. W. R. Dunstan, F.R.S., Director of the Imperial 
Institute, very kindly allowed me to decalcify and examine two 
pearls from this locality, which were taken from among those on 
exhibit in the Papua Court at the Imperial Institute. These 
specimens had recently been sent home, by direction of the 
Administrator, the Hon. M. Staniforth Smith. 
The pearl-banks occur on the western side of Kiriwina Island, 
[86] 
