from the inner surface of two greatly expanded arms which are reflected back across the body. This delicate shell is a pure pearly white and greatly convoluted.
Close to this is a glass model of the squid. Differing considerably from the snail, the typical mollusc, it possesses several peculiarities worth noticing. One portion of the original foot of the mollusc forms the long tentacle-like bodies, the arms, which are provided with suckers for fastening on to its prey. It is in the midst of these arms that the mouth is placed, so that the mouth may be said to be in the middle of the foot. Another portion of the foot forms the syphon, a tubular structure on the under side of the body; and from this the squid is able to project a quantity of inky black fluid, sufficient to cloud all the surrounding water, and cover the animal's retreat from more powerful enemies. Having no external skeleton, the living squid is soft and limp, but on dissection there is found extending along the back and just below the surface, a long thin horny substance, the pen. From the presence of this, and the inky fluid above mentioned, the squid is known as the "pen-and-ink" fish.
There is another curious internal skeleton here exhibited, belonging to a different species of sepia, found on Australian coasts, which is utilised for making tooth-powder. It is formed of a thick layer of soft calcareous matter, and being oval-shaped and somewhat in the form of an ordinary valve, this cuttle-bone is at times mistaken for the external skeleton of some unknown mollusc. Of essentially the same structure as the squid is the octopus, the dread of sea-bathers. In its skin are numerous pigment spots, by contracting and expanding which, it can change its colour in accordance with the region over which it passes. This, no doubt, is a means of safeguard against enemies, as well as affording a cover under which to attack its prey. A very large specimen of octopus, formerly in the Museum, was sent to the Indo-Colonial Exhibition, and thence to the Dublin Museum.
The visitor has now looked through the inner desk-cases of the upper and lower galleries. To continue, let him retrace his steps, this time, however, examining the wall-cases. First of all, he will see on the western side the New Zealand invertebrata, the foreign specimens of which he has already
