WAYS OF THE WILD.

Auckland Star, Volume LXVII, Issue 235, 3 October 1936, Page 1 (Supplement)

WAYS OF THE WILD.

THE OCTOPUS AND ITS ALLIES, i feeding and other habits.(By A. "W. B. POWELL.) Feared and loathed by all, little cafli be said in favour of the octopus except that it represents the most highly developed of all the shellfish. At a glance the claim an octopus may have to the society of true shellfish is not at all apparent. Nevertheless a survey of obviously related animals such as squids and cuttlefishes, which have degenerate internal shells, shows that the octopus represents a successful culmination of the endeavours of these creatures to abandon the ancestral shell covering and to rely for protection upon swiftness of motion and aggressive behaviour. Locally, one has little to fear from the octopus, as they seldom. reach a large size, and in any case do not occur abundantly around Auckland. One meets with them occasionally, however, lurking under rock ledges in the seaweed belt below low tide mark, particularly in the Rangitoto Channel. Occasionally the eggs are washed ashore after storms. They are curious, pure white bunches of short, peapod-like capsules, usually attached to seaweed. The octopus feeds mostly upon shellfish, sometimes crawling over a cockle bed and clinging on to numbers of the cockles by means of the sucker bearing arms. It then crawls back to a cavern or under a ledge of rock and settleg down to eat the cockles at its leisure. If disturbed, the octopus clouds the water with an inky fluid, and is then able to make a retreat under cover of the discoloured water, just like the smoke screens used by battle fleets in modern warfare. This fluid was the origin of the artist's sepia colour, which was formerly made from the octopus.

Can Change Colour at Will. Another curious characteristic of the octopus is that it can change the colour of its skin at will, and in a few seconds one may change from dull grey to a bright orange colour. The formation of the octopus is peculiar; sucker-bearing arms surround the mouth, which is armed with a pair of powerful jaws, shaped just like tlie beak of a parrot. These arms serve in grasping the prey and conveying it to the mouth. The arms probably had their origin in an ordinary type of foot similar to that of the snail. The octopus, preferring to swim rather than to crawl, has adapted the foot to its own special purpose. I have already mentioned how the octopus uses its sucker-covered arms in feeding, but they can be used also for swimming and also in defence. In swimming tlie octopus seems to spread out its arms and then catapult its body forwards, repeating the actions so frequently that a considerable speed ia attained. It is strange that the most beautiful of all shells, the exquisite white papernautilus, should be formed by a creature very closely related to the despised octopus. A very curious thing about the paper-nautilus is that the shell is not attached to the body of the octopuslike animal that forms it, and also that the shell is found in the female only. She uses this shell as a nest or a cradle to hold the large number of. eggs and carries the shell about with her by clasping it with two broad thin arms specially adapted for the purpose. The female paper-nautilus sometimes grows a shell up to nine inches across, but the male never has a shell, and is only an inch long even when fully grown. Some members of the octopus-like class are among the world's largest living creatures. Giant squids, as they are called, have been recorded up to 70ft in total length, and even in Ivew Zealand we have records of two, each one over COft in length, that were washed ashore at Lyall Bay, near Wellington, between 1881 and 1887.

These squids have longer bodies than the ordinary octopus, and there are a pair of fins at one end of the body, and long arms with suckers at the opposite end. The octopus has eight arms, but the squids have ten, two of them being very much longer than the rest. Monsters in Battle. Giant squids are seen only at rare intervals, and even then usually at night. Also, in all probability, most of the stories concerning sea serpents ( are based tpon glimpses that people have had of the long arms of these squids. There are instances on record of fights between the sperm whale and the giant squid, and frequently whales are caught that have scars on their sides suggestive of conflicts with squids. There are many old legends and ancient drawings of ships being overwhelmed by giant squids and Ave must admit an element of truth in them. A miniature squid only two inches in length is found in Auckland waters during the summer months. Last January I secured a number in a net at Matiatia, Waiheke Island, and what these creatures lacked in size was compensated for by their brilliant colouring. They looked like translucent emeralds spotted all over with irridescent crimson and gold. Close relatives of the squids are the cuttlefish, which differ only in having an internal shell remnant in the form of the well-known cuttle bone. Squids, on tlie other hand, have the degenerate shell in the form of a horny, transparent, feather-like structure. Although fragments of cuttle bone wash ashore in New Zealand it is doubtful if cuttlefish actually live in local waters for their buovant internal shells aic la to drift long distances. Some years ago I found an example of the tro pearly or chambered nautilus cm the Ninety-Mile Beach, but as the chambers in this shell are airtight the shell floats indefinitely, so this occurrence on a New Zealand beach is of no more significance than that of a corked bottle.

The Ram's Horn Spirula. One other member of this extraordinary class deserves mention ar.d that is the curious little rain's horn spirula, which is really the internal shell of a small squid-like animal. This little white shell is only about an inch fong, and it is in the form of a flattened open spiral, after the style of a watch spring. It is divided into numerous chambers like a true nautilus, each partition being curved and resembling a beautiful pearl. Millions of these shells are cast ashore every year, particularly on our west coast beaches, yet the amazing thing is that only one living specimen has been found so far in Xew Zealand waters. The species is world-wide in distribution and it was not until 1922 that it was found exactly where the spirula lives. After many unsuccessful attempts the staff of the Danish research ship Dana caught numbers of them in nets far from land in the mid-Atlantic, and neither at the bottom of the sc nor on the surface, but at various intermediate depths ranging from 600 to 6000 feet down.