Lectures on the comparative anatomy and physiology of the vertebrate animals : delivered at the Royal College of Surgeons of England, in 1844 and 1846. Part 1 Fishes / by Richard Owen.
- Richard Owen
- Date:
- 1846
Licence: Public Domain Mark
Credit: Lectures on the comparative anatomy and physiology of the vertebrate animals : delivered at the Royal College of Surgeons of England, in 1844 and 1846. Part 1 Fishes / by Richard Owen. Source: Wellcome Collection.
Provider: This material has been provided by Royal College of Physicians, London. The original may be consulted at Royal College of Physicians, London.
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![In the numerous classes of animals which constituted that inferior, more extensive, and diversified group, linked together by the single negative character of the absence of a vertebral column, and thence termed “ Invertebrata,” we saw that, as the several series became ele- vated in the scale of organisation, they diverged from one another by reason of the preponderating development of some particular class of organs, and culminated in species, inferior either in their general form, or their powers of motion and perception, to some of the antecedent forms, through which the series had passed.* The spider and the crab are not the kinds of animals in which one should have anticipated that the type of organisation, so richly varied in the Insect class, Avould have ended, had that class been a step in the direct progress to the vertebrate series. The loss of wings, and the abrogation of the power of flight, would indicate a retrograde course of development. In the in- sect, the animal organs, more particularly those of locomotion, prepon- derate over the vegetative or plastic organs, and in the attempt, as it were, to restore the balance, by establishing, as in the Crustacea and .^achnida, a better defined system of circulation, and a more vigorous and concentrated heart, the general plan of the articulate structure appears not to be such as to bear this adjustment without a sacrifice of some of the faculties enjoyed by Insects. So likewise the route of organisation traceable through the molluscous type seems, on the other hand, to lead to an extreme subordination of the motive and sensitive to the vegetative systems. And in those species which make the nearest approach to the Vertebrata, we find the viscera of organic life occupying so large a proportion of the body, that no room is left for the development of nervous or muscular organs, except by what seems an undue expansion and overloading of the head, as, for ex- ample, in the Cephalopoda. In fact, the nervous system, the essence and prime distinction of the animal, had not, so to speak, any proper or defined abode in the bodies of the invertebrated animals. Its centres were sometimes dispersed irregularly through the general cavity of the body, sometimes aggregated around the gullet, some- times arranged with more symmetry along the abdomen ; yet seldom better cared for or protected than the neighbouring viscera. The grand modification, by which a higher type of organisation is established, and one which becomes finally equal to all the contin- gencies, powers, and offices of animated beings, in relation to tliis ])lanct, is the allocation of the mysterious albuminous electric pulp in 'a special cylindrical cavity, of which the firm walls rest upon a basal * Iluntvriun l.etliircs, IiivLnlclji'at;i, 8vo. IS'lO. fl S'](https://iiif.wellcomecollection.org/image/b28270472_0021.jp2/full/800%2C/0/default.jpg)
