Intermembral homologies : the correspondence of the anterior and posterior limbs of vertebrates / by Burt G. Wilder.

  • Burt Green Wilder
Date:
1871
Catalogue details

Licence: Public Domain Mark

Credit: Intermembral homologies : the correspondence of the anterior and posterior limbs of vertebrates / by Burt G. Wilder. 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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    the entire habit of fishes, and with their mode of life, they best iudi- eate their natural ailinities, and indeed prove to be the most constant and q-(jiicral characters.” As to o-eneric criteria, Midler and Heiile enumerate ^ the eharae- ters found by them most useful among Selachians; and Parker is explicit respecting the unimportance of certain characters, for the detei’miuation of groups more eompreheusive than genera.^ Specific characters of the Pycnogonidre are enumerated by H. P). S. Goodsir,^'and those of the tortoises by Owen (62, 1, 162.) Finally, a great ]Dart of Agassiz’s later works (200 and 201), is de- voted to the effort to show not only that groups really exist in na- tm-e, but that they are based upon distinct “ categories of structure.” I quote the following also fi-om my notes of his lectures on Selach- ians.^ “ Zoologists take very different criteria or different parts as foundation for the same kind of group», or the same criteria for dif- ferent kinds of groups, so that their results are very diverse. We must have some means of determining the value of characters.” Accepting provisionally Agassiz’s abstract enunciation of these cri- teria and them subordination as to value, as summed upon page 261 of 201, and likewise considering the only direct application of these prin- ciples to a single group, the Testudinata and its subdivisions (200, 1, Part ii), I have endeavored to translate the zoological criteria into anatomical language, and in this way to at least indicate the means by which we may sometimfi be able to determine the exact morphi- cal value of any anatomical character. The conclusions which I reached are given in the diagram (page 28), and afterward briefly explained; but I must here admit that I feel sure of being right upon only the following points : ° ° 1. That both plan of structure and form are displayed upon a vertico-lateral section of an animal.® ' Aim. and Mag. of Nat. Hist., 1844, pp. 1 and 4. >Proc. Zool. Soc., 1863, p. 672. ’ Ann. of Nat. Hist., July, 1844, p. 1. < Given at the Museum of Comp. Zool., 1867 - 1868. '■•As between Vertobrata and Kadiafa, or between either of those and the Mol luscaand Articulata this is clear enough; but since the relative positions of di pstive, nervous and circulatory systems seem nearly identical in^tlio two latter branches, the respiratory and perhaps some other systems must bo ^ or . L nX As to the view that Vertobrata and Mollusca may lliid connoctlL mn-c ^ ’ V f!' oxuH and the Ascidians (references to which are given in a%) I have not' 8
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