PROCEEDINGS.—APPENDIX.
∵ Owing to the absence of the Editor, these papers were omitted from their proper place in the Proceedings.—Ed.
On the supposed Influence of Climate over the Geographical Distribution of the Marine Mollusca. By C. W. Purnell.
[Read before the Otago Institute, 1st August, 1876.]
abstract.
The author states that it has always been assumed by malacologists that climate, in its broad gradations, has a large direct influence over the geographical distribution of the Marine Mollusca, but various considerations have led him to believe this to be an entire mistake, and that if climate exercises any influence at all in this respect, it does so indirectly, as by regulating the supply of food.
That in the first place, the comparatively low nervous organisation of the Marine Mollusca seems to warrant the inference that these animals are but little susceptible to the extremes of heat and cold; and he apprehends it is the nervous system which primarily feels climatic influences.
Next, he says, we are struck with the immense range of space over which numerous families and genera of the Marine Mollusca, even the most highly organised, are spread. The Cephalopoda are conspicuous for their world-wide distribution. The Octopods, for example, which abound on the coast of New Zealand, and specimens of which are frequently thrown up at the head of Dunedin harbour, are found floating about all seas, under every climate. They are plentiful in the tropical Indian seas and in the warm waters of the Mediterranean, while one genus—Cirroteuthis—dwells as far north as the coast of Greenland. The calamaries and cuttles are likewise dispersed all over the world.
The same conclusions are reached by examining the distribution of the other classes of the Mollusca.
The author then gives a list derived from the published writings of Woodward, Adams, and other malacologists of recognised authority. The list is not exhaustive, but illustrative only. It shows that molluscs of the same genera are to be found in every latitude, from Nova Zembla to the hottest regions of the tropics, and every class is thus represented. The icy seas furnish a home for the higher as well as the lower forms. On the coast of Labrador, for example, Mr. A. S. Packard, a naturalist, states that 43 species of marine bivalves, 57 marine Gasteropods, one Brachiopod, and one Cephalopod (Ommastrephes todanus), have been collected.
