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but differs from that species in being of a larger size, in the lighter 
hue of the centre of the abdomen, in the strize down the centres of 
the abdominal feathers being less strongly defined, and in the under 
tail-coverts being buff instead of rufous. 
3. Sirra LEucopsis, Gould. 
Sp. Ch.—Crown of the head and back of neck jet-black ; all the 
upper surface deep blue-grey ; primaries black, edged with grey ; 
centre tail-feathers blue-grey ; lateral feathers black, tipped with blue- 
grey ; the two outer ones on each side with a small spot of white on 
the inner web near the tip; face, chin, throat, breast, and centre of 
the abdomen white, the latter slightly washed with buff; flanks and 
under tail-coverts bright chestnut ; bill black, with a blue-grey base ; 
legs grey. 
Toral length, 5 inches; bill, 7; wing, 32; tail, 2; tarsi, 2. 
Hab. The Himalaya Mountains. 
Remark.—This is doubtless the species described by Mr. Blyth in 
his observations on the Sittin as nearly allied to the S. cesia, 
without however assigning to it a specific name, an omission which I 
have now ventured to supply. 
4. ON THE sPecIES OF ANoMIADH. By J. E. Gray, Esa., F.R.S. 
; ETC. ETC. 
The European species of Anomiade have been much multiplied, 
while on the other hand the exotic species have been almost entirely 
neglected. 
The form, substance, surface and colour of the shell, which have 
been used to distinguish the species, were suspected by Montague to 
be dependent on the age of the specimens and the locality in which 
they happened to be found, and further researches have proved the 
accuracy of these observations. 
There being in the British Museum considerable series of speci- 
mens of this family from different localities, I have attentively exa- 
mined them, and believe that I have observed some characters by which 
they may be distinguished from each other, which are but little, if 
at all, modified by external circumstances or age. 
Mr. Cuming has kindly allowed me to examine the original spe- 
cimens of Placunanomia, described by Mr. Broderip, with some ad- 
ditional specimens which he has since received, and thus enabled 
me to identify the exotic species which have been described by that 
naturalist ; and also the collection of Anomie contained in his cabi- 
net, which has furnished me with several additional species. 
The species may be divided into two very distinct genera :— 
1, Anomia. Upper valve with three subcentral muscular scars ; 
the anterior upper lobe of the notch separated from the cardinal edge ; 
the plug entirely shelly, and quite free from the edge of the notch. 
2. Puacunanomia. Upper valve with two subcentral muscular 
sears ; the anterior upper lobe of the notch agglutinated to the car- 
dinal edge; plug shelly at the top and near the body to which it is 
attached, and with horny longitudinal lamin below and internally. 
No. CXCVII.—Procerpines or THE ZooLocicaL Soctery. 
