bo 
62 DR. H. LYSTER JAMESON ON 
to Mr. E. Hopkins, of Hatton Garden, for specimens of Ceylon 
Pearls; to Professor W. A. Herdman, F.R.S8., for specimens of 
Pearl-Oysters from Ceylon, and for allowing me to examine his 
preparations ; to Mr. Max Mayer, of Hatton Garden, for specimens 
of pearls for my work; to H.H. the Jam Saheb of Nawanagar, 
for specimens of Pearl-Oysters from the Gulf of Kutch ; to Prof. 
L. G. Seurat, for pearls from New Caledonia, Madagascar, and the 
Gambier Archipelago; to Mr. A. E. Shipley, F.R.S., for allowing 
me to examine and make use of his specimens of J'ylocephala and 
allied genera of Cestodes from Ceylon fishes; to Mr. E. A. Smith, 
1.8.0., for permitting me to make use of material in the British 
Museum (Natural History), including specimens from Dr. Kelaart’s 
collection; and to Mr. A. Van Noorden (of the firm M. Myers, 
Mother-of-Pearl Merchants) for specimens of Lingah and other 
shells. 
After this paper was handed in I received a copy of Rubbel’s 
paper (34a) setting forth in greater detail the results already 
published by him (33 and 34). Herr Rubbel and I have arrived, 
working independently on widely different molluses, at identical 
conclusions on several important points, such as the nature of 
Herdman’s ‘“calcospherules.” Where practicable, I have inter- 
polated references to his work in the text, and my only regret is 
that it is not possible to discuss his valuable work more fully in 
the present paper and to dwell at length on the many points where, 
adopting a slightly different terminology and interpretation of the 
phenomena, our respective works lead to the same conclusions. 
(2) OUTLINE OF THE RECENT INVESTIGATIONS IN CEYLON. 
In January 1902 Professor W. A. Herdman went to Ceylon, at 
the request of the Colonial Office (who availed themselves of his 
services on the recommendations of the Council of the Royal 
Society and of Professor Ray Lankester), to investigate the 
condition of the Pearl-Banks. Professor Herdman took with him 
as his assistant Mr. James Hornell, who remained in Ceylon to 
carry on the work after the former’s return to England in April 
of the same year, and who collaborated in the preparation of 
Professor Herdman’s reports. Professor Herdman’s visit in 1902 
gave him seventy-eight days in Ceylon, and was largely spent in 
an extensive biological and faunistic survey of the pearl-banks, 
carried out on two successive dredging-cruises, each of several 
weeks’ duration ; and he credits Mr. Hornell with the major part 
of the observations on Pearl-production (Royal Institution 
Lecture of March 27th, 1903) (14). Prof. Herdman himself 
always seems to have regarded the condition and welfare of the 
natural beds of oysters as a more important problem than the 
question of pearl-production (Report on the Ceylon Pearl 
Fisheries, Part I. p. 5, and Part V. p. 29; also Report of the 
Annual Meeting of the Ceylon Company of Pearl Fishers, Ltd., 
[4] 
