examined. Then follow on the northern side, the New Zealand fishes. Among the spirit specimens may be noticed the ribbon-fish, like a long and slender band of silver, and the originally transparent glass-fish, which has unfortunately become opaque in the spirit.
Attention should be directed to the fact that the skeleton in the skate and lower fishes is cartilaginous. The skeleton in fish, however, as we ascend the scale becomes a bony one, and as in all the higher animals, forms the main support of the body. In the shark will be seen the five gill-slits, with a small hole just behind the eye. In higher fishes, these become covered by a bony plate, the operculum, which hides from view the gills beneath it. Then again, a further development is seen in the respiratory organs, in the Australian mud-fish, which in winter breathes by gills in the ordinary way, but in summer when the rivers are low, breathes air by means of lungs.
In the wall-cases along the eastern side of this gallery are some good fossil remains of fish, showing the skeleton almost intact.
Besides the ordinary collection of animals, the Museum possesses an excellent assortment of skeletons, both natural and disarticulated. The disarticulated skeleton of the New Zealand ling illustrates what a difficult task it is to thus arrange and preserve all the separated bones in their correct relative positions.
Amphibia, represented by frogs, are the next advance on fishes, and living as their name implies, part of their life above, and part under water, have necessarily more fully-developed respiratory organs.
The next exhibits of special interest are sets of models showing the development of the chief types of animals, and of the eye and skull in vertebrata. Those illustrative of the frog, show first the undivided egg-cell, then as it appears divided into two, into four, into eight parts, and so on into an innumerable mass of cells. This mass next develops cavities, and gradually shapes itself into a tadpole with external gills. The tadpole is a water-breather, and exists chiefly on vegetable food. After living for a time in the water its external gills disappear, and respiration is carried on by internal gills; but then comes a further change, which is illustrated in the models. The opercu-
