Address to the Zoological Section / by G. B. Howes.

  • Thomas George Bond Howes
Date:
1902
Catalogue details

Licence: In copyright

Credit: Address to the Zoological Section / by G. B. Howes. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    As to the nature of this unprecedented progress, it will suffice to consider the Earthworms. In 1874 few were known to us. An advance in our knowledge, which had then commenced, had made known but few more which seemed likely to yield result. Darwin’s book upon them had not appeared. Some were exotic, it is true, hut no one suspected that a group so restricted in their habits could reveal aught beyond a dull monotony of form and structure. Never was surmise more wide of the mark, for the combined investigations of a score of earnest workers in all parts of the world have in the interval recorded some 700 odd species of about 140 genera.* Mainly exotic, they exhibit among themselves a structural variation of the widest possible range. Not only do we recognise littoral and branchiate forms, but others achaetous and leech-like in habit, to the extent of the discovery of a morphological overlap with the leeches, under which we are now compelled to remove them from their old association with the flat worms, and to unite them with the earthworms. And we even find these animals, as represented by the Acmithodrilidce, coming prominently into considerations which involve the theory of a former antarctic continent, one of the most revolu- tionary zoo-geographical topics of our time.® This case of the earthworm may be taken as typical of the rest, since for each and every class and order of animal forms, the progress of the period through which we have passed since last we assembled here has produced revolutionary results. Our knowledge of facts has become materially enhanced ; our classifications, at best but the working expression of our ideas, have been to a large extent replaced in clearer, more comprehensive schemes; and we are to-day enabled to deduce, with an accuracy proportionate to our increased knowledge of fact, the nature of the interrelationships of the living forms which with ourselves inhabit the earth. Satisfactory as is this result, it must be clearly borne in mind that its realisa- tion could not have come about but for a knowledge of the animals of the past; and turning now to palseontolog-y, it may be said that at the time of our last meeting in this city the scientific world were just becoming entranced, by the promise of unexpected results in the exploration of the American Tertiary beds, then being first opened up. The Rocky Mountain district was the area under investigation, and with this, as with the progress in our knowledge of recent forms, no one living was prepared for the discoveries which shortly came to pass. To consider a concrete case, we may premise that study of the placental mammals had justified the conclusion that their ancestors must have had equal and pentadactyle limbs, a complete ulna and fibula, a complete clavicle, and a skull with forty-four teeth ; must have realised, that is, the predominant term of the living Insectivora as generally understood. Who among the zoologists of our time does not recall with enthusiasm the revelation which arose from the dis- covery, during these early days, in the Eocene of Central North America, of the genera at first ^escribed as Eo- and Helohyus ? ’’ The evidence of the existence, in the locality named, of these forty-four toothed peccaries, as they were held to be, rendered clearer the records of the later Tertiary deposits of the old world, which were those of hogs, and, in correlation with the facts then known, suggested that the Rocky Mountain area was the home of the ancestral porcine stock, and that in Earlv Tertiary times their descendants must have migrated, on the one hand, across the northern belt, of which the Aleutian Islandsnow mark the course, into the old world, to beget, with complication of their teeth, the pigs and hogs ; and on the other into Central South America, to give rise, with numerical reduction of teeth and toes, to the peccaries, still extant. Migration in opposite directions with diversity of modification was the refrain of this remarkable find, far-reaching in its morphological and zoo-geographical effects. Nor can we allude with less fervour to the still more striking case of the horses, indicating not merely a similar, though perhaps a later, migration, but a parallelffim of modification in both the old and new worlds, culminating in the latter in extinction, whereby it became necessary, on the advent of civilised man, to carry back the old-world horse to its ancestral American home. No wonder that this should have provoked our Huxley to the remark that in it we have the