Prof. R. Dubois has recently turned his attention to the 
Mediterranean Coast. He found that the Southern French 
mussel (Mytilus yallo-provincialis) forms pearls caused by 
another Distomid, distinet from that of Brittany. He then 
worked at the acclmatisation of a true Oriental Pearl- 
Oyster (‘‘ Pintadine’’) in French waters, and the artificial 
production of pearls.* He brought the pearl-oysters from 
the Gulf of Gabes, in South Tunis, to the marine laboratory 
at Sfax, and caused them to multiply and increase in size. 
The pearls produced in Tunis are small and very rare— 
it is necessary to open 1,200 to 1,500 oysters to find one 
pearl: but Dubois tells ust that by placing them on ground 
where Mytilus gallo-provincialis becomes infested with 
pearls and parasites, he very easily provoked the pro- 
duction of fine pearls in the “ pintadine ” to such an extent 
that three successive individuals opened contained each 
two little pearls. 
This, if corroborated, is a remarkable circumstance 
from several points of view. First it will, if it proves a 
success, be a striking verification of what Kelaart in 
Ceylon, fifty years ago, declared might be done. Secondly, 
if the ‘‘pintadine”’ in question is really the same species 
as the Ceylon Pearl-Oyster (Giard considers that it is not), 
it is curious that a Distomid parasite should prove to be 
so efficacious in setting up pearl-formation, since Mr. 
Hornell and I found in the Gulf of Manaar that the 
pearl-parasite is a Cestode of the genus T'etrarhynchus. 
Thirdly it is remarkable that the parasite of the Mytilus 
should transfer itself so readily to a new host belonging to 
a distinet family. 
* Comba had, however, in 1898, introduced the same molluse on 
the south coast of Italy, and experimented in artificial pearl 
formation. 
+ Comptes rendus, Acad. Sci,, 19th October, 1903, p, 611, 
