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3. Critical Note on the latest Theory in Vertebrate Morphology

Published online by Cambridge University Press:  15 September 2014

J. T. Cunningham
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Extract

In the attempt to trace the vertebrate organisation by comparative anatomy and embryology back to a simpler state, the origin of the limbs has been made the subject of various hypotheses. Many years ago Gegenbaur brought forward a method of regarding the morphology of the limbs, by which each could be derived from a gill arch supporting a series of gill rays, from such a system as forms the skeleton of a gill in a typical Selachian of the present day. This comparison was instituted without any particular stress being laid on the relation of the ancestral vertebrate to invertebrate forms. He supposed that the central ray of the series in the branchia gradually grew more prominent, and as it increased in length the rays near it lost their attachment to the arch, and became articulated to the sides of the central ray : in this way he obtained an imaginary limb skeleton which he called the Archipterygium.

Type
Proceedings 1882-83
Information
Proceedings of the Royal Society of Edinburgh , Volume 12 , 1884 , pp. 759 - 765
Copyright
Copyright © Royal Society of Edinburgh 1884

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References

note * page 761 Urspmmg der Wirbelthiere, Leipzig, 1875.Google Scholar

note † page 761 “Studien zur Urgeschichte des Wirbelthierkörpers VI.” Mittheil. aus der Zoologischen Station zu Neapel, Band V. Heft 1.

note * page 764 Laichen u. Entwicklung des Ostsee Herings, Berlin, 1878.Google Scholar

note † 764 Having carefully studied the development of the herring in the month of August, I can fully confirm Kupffer's description of the newly-hatched larva. The proportion of the length of the body through which the pre-anal ventral fin extends is considerable, the whole length of the larva being 5·2 mm., while the length of the pre-anal fin is 2·5 mm. The larva of the herring is closely similar to the first larva described above; it is quite transparent; the yolk consists of separate spherules, and the notochord has but one column of cells. (Note added Sept. 19, 1884.)