109 
In other countries, spurious Pearls have been pro¬ 
duced, for an equally laudable object, by placing 
pointed pieces of wire in a similar situation. 
Case 88 contains the shells of Branchiopodous Mol- 
lusca, which are inclosed by two regular shelly valves. 
They have no distinct head, but the mouth is placed on 
the hinder part of the cavity, and is furnished with two 
long spirally twisted arms, by which they reach their food; 
the organs of respiration are placed on the edge of the 
mantle. All these shells are attached to marine bodies : 
some of them are regular, and somewhat like a Grecian 
lamp in form, and have therefore been called Lamp- 
shells. They are attached by means of a tendinous band, 
which passes out of the hole in the apex of the upper 
valve, as in the Terebratulce and Spiriferi: others, as in 
the Lingula, are attached by a tendinous tube, resembling 
the stem of the Barnacles, which passes out between the 
apex of the valves, w hich gape in front. The Discince , on 
the other hand, have the tendon passing out of a linear 
slit near the middle of the under valve; and the Cranice 
are immediately attached by the outer surface of their 
shells. 
LONG GALLERY. 
The Long Gallery above the King’s Library is 
appropriated to the collections of Mineralogy and 
Secondary Fossils, the arrangement of the latter of 
which is not yet completed. The system adopted for 
the arrangement of the minerals, w'ith occasional slight 
deviation, is that of Professor Berzelius, founded upon 
the electro-chemical theory and the doctrine of definite 
proportions, as developed by him in a memoir read 
before the Royal Academy of Sciences at Stockholm, 
in 1824. The detail of this arrangement cannot here be 
entered into: it is, however, partly supplied by the 
running titles at the outsides of the glass cases, and 
by the labels within them. 
The first two cases and part of the third contain the 
electro- 
ROOM XIII 
Nat. Hist. 
LONG 
GALLERY. 
Nat. Hist. 
