162 
ZOOLOGICAL COLLECTIONS. 
[UPPE R 
shells, some of them weighing more than 300 pounds. The Phola- 
dacea, or Boring shells, live sunk perpendicularly in holes in rocks, or 
in sand. Tables 39-48 contain the Asiphonophora, which have the 
mantle-leaves free, and sometimes a separate single siphonal opening, 
for the emission of the water, as the Mussels and Oysters, many of 
which secrete pearls ; the brightly-coloured Spondyli, or " Thorny 
Oysters," with their rough, foliated or spiny shells, and the thin 
Placunae, or " Cake-Oysters," which are semi-transparent. 
In Table 49-50 are shells of the Mollusca which have no distinct 
foot on the under side of the body, and which either live attached to 
marine bodies (Brachiopoda), or float on the surface of the sea (Ptero- 
poda), or walk by means of the tentacles placed round their heads 
(Cephalopoda). The Pteropoda have an expanded fin on each side of 
the small foot. Of these the Limacina and Clio are so abundant in 
the Arctic Seas as to form a great part of the food of the whale. The 
Cephalopods (of which the Cuttle-fish and Octopus are examples) have 
eight, ten, or many strong and elongated arms round the mouth of 
their large and distinct head : the mouth is armed with large beak- 
like jaws. When swimming their motions are rapid. Their eyes are 
large, and their back is generally supported with an internal horny 
blade, sometimes strengthened with a shelly coat, as the cuttle bone. 
They have a secretion of a deep black colour, which they emit when 
in danger, and thus conceal themselves. They are very voracious. 
The Paper Nautilus (Argonauta) fabricates a delicate symmetrical shell. 
The Pearly Nautilus forms a shell which is divided into chambers, the 
animal inhabiting only the outermost. Some of the extinct chambered 
shells, as the Ammonite, are placed with the Nautilus Shell in Table 50. 
In some of the side Table Cases there are — a series of specimens ex- 
hibiting the structures, diseases, deformities, and reparations of shells, 
such as the distorted variety of the common Garden Snail, described as 
Helix cornucopia ; a series of the eggs and egg-cases of Molluscs ; a 
series of specimens exhibiting the shells used for commercial purposes, 
such as the cameos, mother-of-pearl, gloves made from the byssus of 
the Pinna, the Chank shells carved by the natives of India and used 
in their temples. In another Case are specimens of the various kinds 
of Sea Slugs (Holotliurice) ; in China and the East Indian Archi- 
pelago they are sold as articles of food, under the name of Trepang. 
Some of the rarest examples of small Quadrupeds are exhibited on 
the Table Cases. The stuffed specimen of the Aye-aye of Madagascar 
shows its large ears, the slender middle finger of the fore-hand, and 
the thick thumb of the hind-hand. The skeleton of the same animal 
shows the strong curved chisel-shaped front teeth : with these the 
Aye-aye gnaws down to the burrows of wood-eating grubs, and with 
its slender hooked finger extracts them. It is nocturnal, arboreal, 
and is guided to its favourite food by its acute sense of hearing. Also 
the curious Chlamydophorus and its singularly formed skeleton from 
Chili, and various specimens of Propithecus and other Lemuridse {see 
p. 6) from Madagascar. At the North end of the gallery stand the 
cabinets containing the magnificent collection of Butterflies recently 
bequeathed l\Y the late Mr. W. C. Hewitson. 
