On the structure and development of the skull in the Batrachia. Part II / by William Kitchen Parker.

  • William Kitchen Parker
Date:
[1876]
Catalogue details

Licence: Public Domain Mark

Credit: On the structure and development of the skull in the Batrachia. Part II / by William Kitchen Parker. 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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    This is, in itself, a most agreeable part of my work; and I hasten to sift away all that appears now to be untrue, however well winnowed it once appeared. The advantages above mentioned are not all, nor even the greatest of those I have of late derived from the researches of my valued fellow-labourer; most suggestive and pro- mising are the views which have lately been laid before the Society (Proc. Roy. Soc.Dec. 17, 1874, vol. xxiii. p. 127) on the Amphioxus and its structural relations to the Lamprey, its larvae, and its kindred. This short paper is, if I am not greatly mistaken, of almost equal value with the £ Croonian Lecture if the author’s deductions stand the test of further research, they will light up the darkest recesses of Vertebrate morphology. I shall suppose the reader to be familiar with that communication, and it will be open to us now to consider the ordinary Yertebrata, or Holocrania, to be highly spe- cialized and metamorphosed descendants of long-lost £ Entomocrania.’ In the latter the long, many-jointed skull may be compared to that part of a plant in which all the ‘internodes’ are developed; whilst the skull of ordinary Vertebrata may he likened to a flower, where the internodes are not developed, and where the foliar organs, being brought nigh to each other, coalesce in various ways and undergo remarkable modifications of form and of relative size. At present I bring forwards corrected figures of the skull of the adult common Frog (.Rana temporaria), and new results obtained by a study of the development of the skull of the common Toad (Bufo vulgaris), correcting, by these observations on equiva- lent stages, those which are imperfect or untrue in the first memoir. In that paper the figures are seldom inaccurate, but both these and the descriptions will be brought now into comparison with these newer results. After this has been done, I shall show the structure of the skull in various stages of the £ Aglossal ’ Toads—namely, Dactyletlira, the Cape Toad with nailed paws, and Pipa, the remarkable Surinam Toad. These will take up all the space available in a single paper; afterwards, my researches on the Bull-frog {Rana pi pirns) and the Paradoxical Frog (Pseudis paradoxa) will, with others, be offered to the Society, and, also, as time and opportunity serve, figures and descriptions of the less-modified tailed types of Amphibia. Such terms as are new in the present paper are adopted from the two memoirs of Professor Huxley just referred to; the gradual introduction of accurate morphological terms is not only desirable but absolutely necessary, yet these cannot be given before the true nature of the parts is understood. In the Class of Fishes the specialization of the parts of the skull and face is greatest in the Teleostei, and least in the Marsipobranchii; the Elasmobranchii come nearest to the latter, the Ganoids nearest to the former; all these types of skull must be brought into light; of my own work only that on the Teleostean skull has as yet appeared. One thing which misled me in working out the Frog’s skull was the expectation of finding its development much more in harmony with that of the Teleostean type than it turns out to he.
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