330 
THE TROPICAL AGRICULTUEIST. 
[Nov. 1, 1901. 
green contents of the cells of the upper rpidermis, 
and by I he disposiiicm of ihe celu aiuiexei to 
the respiratory appitratns These are so pUced 
a« to have lli'4r long axis p ii allel to th^^ o!«tiole. 
Of the various reagents siigtiesied tor ihe histolo- 
gico clieniial exainum.tion of niaie, Cador prefers 
concentrated hydrochloric acid and i three-per- 
cent solution of gold chloride. By means of i liese 
re-agents well-dehned giinips of crystals •f ihe 
double chloride of gold and caffeine are obtaineil. 
The reaction i'^ parHcul rly marked in the case 
i)i Ilex parayvaimsis — Chemist and Druggist, 
Augnst 31. 
PEARL OYSTERS. 
Mr. Lyster-.Tamesi)n, b.a. Ph. d., sent us by 
a recent mail a copy of his pai)er :- " On the 
identity and distribution of the Mother-of- 
Pearl Oysters : with a revision of the Sub- 
genus MargarititVra "--reprinted from the 
proceedings of the Zoological Society of 
London, April 16th, 1901. This instructive 
paper, of some 23 pages, opens :— 
" Acting upon a su-;gestioii made to me by Pro- 
fessor E Ray Lankes:er, I have recently b^en 
entrat-'fd in rearranging the collectinn of Mar- 
garitiferce in the British Museum of Natural Hrj- 
iory, and in revising and extending the series illus- 
trating the commercial forms. The nomenclature 
of these forms has hitherto been in a chaotic 
state, and it ha? occurred to me that this revi- 
sion of the genus may be worth publication if only 
to prevent further confusion of the common com- 
mercial forms by zoological aiul e 'onomic wiiters." 
Can Mr. Lyster-Jameson be coming out with 
Professor Herdman to Ceylon, Professor E. 
R. Lankester having been originally con- 
sulted by the Colonial Office ? The passage of 
special interest to us in Ceylon, in the paper 
is the one sve quote below : — 
MOTHER OP PEARL OYSTERS. 
(From paper by H. Lyster Jameson, B. A., Ph. D.) 
Species 13. Magaritifera vulgaris. 
Perlamater vulgaris Schumacher, 1817 p. 108, pi, 
XX. fig 8 ; no loc. 
Chfuinitz, 1785, tab 80. fig. 717 (referred fo by 
Schumacher a/* a second figure of hi-^ P vulgaris). 
Avicula fucata, Gould, I85u, p. 3u9 1852. p. 441,- 
pi. 39. fig. 551 ; New Zealand 
Avicula jucata. Reeve, 185T, sp. 74 ; Japan. Type 
in B M. 
Avicula occa, Reeve, 1857, sp. 24 ; Red Sea. Type 
in B M. 
^yicM-te rtemto, Eeeve, 8157, sp. 32; Australia. 
Type in B M. 
Avicxila perviridis Reeve, 1857, sp. 2o ; Aus- 
tralia Type ill B Vi. 
Avicida (Meleagiina) raria, Dunker, 1872, p. 17, 
tab. 4. fig. 6 ; Ktd St-a. 
Avic^ila ( Mdeaq^inaj badia, Dunker, 1852, p. 
79 ; 1872 p. 12 tali. 2 fig. 7 ; no loc, 
Savigny, 1811, pi. 11 figs. 8 & 9. 
As Schumacher's figure, and ihe one by Chrinnitz 
to which he refers, are evidently typical Eastern 
Lingah shells (from convexity, posterior ■'auiicle" 
of hinge-line, sharp separation of the inner surface 
of the rostrum from the general surface o( the 
nacre by a well-defined ridge, and distinct anterior 
and lateral teeth in Schumacher's figure), the 
name vulfjaris must replace the more faniiliar 
fucata (Gould) for thie specieB. 
This shell is extremely variable, and young ex- 
amples have been described as (ii>iiint .••pi-i ies ovt-r 
and (ivei again, while, uiiiil com|iKiauvfly lecent- 
ly. tliegiinvn shell has been confu.^eil by many 
writers with M maryaritif'i ra. 
It is highly probable that some of the described 
forms which I am still treating as separate species 
will, on belter acquainlancp, prove to be merely 
geographical races of M vulgaris Sehumiicher, 
Geoyrajihical Distribution ond Variation : — 
Ceijlort and Soulliern India. The ( 'e>lon Pearl- 
Oystei i« ihe best knou n li.ciil toim of liiis species. 
It fr>qnents the Gulf of Mauaar, Palk Straits, and 
the Southern coast of Intlia. It differs from most 
other local laces iu its lighter colour, and tlie 
whitish or pink ground-colour of the interior of the 
lip. 
Maldive Islands. Mr J Stanley Gardiner, on 
his recent vioit to the Maldives found this sptcies 
faiily pleniifnl there, but not in extensive neds. 
JJnUkt: 1\1 .maTgaritifera,\.\uh shell i- not fished by 
the natives of tiie M ihiives. Mr Gardiner's speci- 
mens closely resembles iliosefrom Ceylon, and were 
at once referred by Captain Donnau to the same 
species. 
Persian Gulf. The Liugah shell of the Persian 
Gu f belong.s lo this species. It is distinguishable 
from the Cej Ion form by its daiker colour, the 
exterior neing usually more purple and the r» lial 
mar kings almost black. Tlie interior of the lip is 
dark red. The shells attains somewhat larger di- 
mensions than in Ceylon walers. It is shipped in 
quaniities to the London luarkets, but is of small 
and fiiu'tuatiiig value, owing to large supply and 
limited demand. 
Red Sea. Throughout the Red Sea this shell is 
common, but is lislied almost exclusively for pearls. 
Tiiere ai e a iiuml er of specimens fiom the Red Sea 
in the British Museum, but with one exception 
(Aden, Mnjor Verbury) they are very young. The 
Aden specimen is very like a Ceylon shell. 
{Uedtterrauean. Since the opening of the Suez 
Canal this spi-cies has wandered into the Mediter- 
ranean. There are typic>il examples from Alexandria 
(W B J'egeimeier) and Malta (Col. Feilden) in the 
Briii-h Museum. An acco'int of this interesting 
immigration has been published by Vassel, 1896.] 
East Africa. Specimens from Mauritius (B M ; 
Mus. Cuming), S. Africa B M ; J. H Ponsonby 
Coll.), Bizanitolsl. (do.), and Durban (do.), al- 
thougli differing siij>luly from normal Lingahs in 
form and mai kings, aie probably merely a local 
race of this very valuable species. I do not leel dis- 
poseil to describe them even as a geographical 
variety on the .small amount of materiaai available. 
Malay Peninsula and Archipela(,o. Specimens 
from Malacca and Singapore in the Brit. Mus. 
are harilly different from Ceyiou examples, I have 
found typical examples associated with the young 
of M marqaritifera in a trade sample from Elores. 
Avstralian Waters. " The Australian Lingah" 
shell of the Loii iou m^irkets, most of whicii comes, 
I believe, from West Au-tralia. and ttie "Bastard 
Shell" of Torres Stiaiis (Pace, 1898) are preferable 
to I bis species. There are inimatnre examples of 
M vulgaris from various localities on the ; orth 
coasts of Australia in the British Mn-eum. Two 
spscimens from Sydney, presented by the Earl of 
Derby, are the most southerly record. On the West 
coast it occurs as far south as Sharks Bay (Saville 
Kent). Australian Lingahs closely resem* 
l)le tboae from tbe Persiao Gulf in colour, 
