Detailed abstracts of papers on 1.- The morphological relations of the nervous systems in the annulose and vertebrate types of organization. 2.- The morphological constitution of the skeleton of the vertebrate head. 3.- The morphological constitution of limbs : communicated to the Cheltenham meeting of the British Association, August 1856 / by Professor Goodsir.

  • John Goodsir
Date:
[1857]
Catalogue details

Licence: Public Domain Mark

Credit: Detailed abstracts of papers on 1.- The morphological relations of the nervous systems in the annulose and vertebrate types of organization. 2.- The morphological constitution of the skeleton of the vertebrate head. 3.- The morphological constitution of limbs : communicated to the Cheltenham meeting of the British Association, August 1856 / by Professor Goodsir. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    Turtles through the anterior nasal opening of the cranium in tte form of a double proboscis. The posterior nar^s in the Tortoises are separated by the combined ento-pterygoids (upper and back part of the vomer) and are bounded by the maxillaries and the palatines, the latter remaming open or ununited across the vault of the palate. In the Turtles, the vault of the palate and the posterior nares present more of the Mammalian aspect, although stUl formed essentially on the type of the corresponding parts in the Bird. This is eiFected by the ethmoidal neurapophyseal plates (palatal plate of the vomer), ivhich lie somewhat above the level of the vault of the palate in the Tortoises, passing down into, and forming an area of it in the Turtles, extending from its posterior margin halfway, or quite up to the intermaxillary palate plates. In the latter arrange- ment the ethmoidal area is hexagonal, and separates the palatal plates of the maxillaries from one another. In the former it is pentagonal; and the palatal maxillary plates meet in the mesial lino in front of it. The palatal plates of the palatines are more or less developed in the Turtles ; and many approach one another at the free margin of the vault, but are always separated by the posterior or free margin of the ethmoidal area. The arrangement of the vault of the palate in the Turtles, and the pe- culiar Chelonian configuration of the pterygoids, lead to the very remark- able combination of Ornithic and Mammalian structure presented by the nasal fossae and jialatal vault of the Crocodiles. The Mammalian charac-. teristics are the full development of the inter-maxillary and nasal bones, with the extensive, although cartilaginous, vomer. The vomerine sclero- tome of the Crocodile is not closed anteriorly as in all the other Lacertians, in the Ophidians, Amphibians, and Birds ; but presents a completely per- forated catacentric arrangement. This complete form of the vomerine necessitates a rhinal sclerotome, which, accordingly, feebly represented in the Crocodiles and Alligators, appears to be more fully developed in the Gavials. The extensive and complete Crocodilian palatal vault is only apparently Mammalian, it is partially Ornithic or Chelonian in its constitu- tion. As in the Mammal the anterior extremity of the vault is formed by the pair of fully formed palatal inter-maxillary jjlates. Except in the Alli- gators in which there is a slight intrusion of the ento-pterygoids, the pa- latal plates of the maxillaries meeting along the mesial line, form the second and most extensive area of the palatal vault. The next area of the vault consists, as in the Turtles, of the ethmoidal neurapoph)'ses (the so-called palatals), united along the mesial line, and much elongated backwards. The posterior margin of the combined ethmoidal neurapo- physes of the Turtle forms the central part of the free margin of the palate ; but the completion in the Crocodile of the deflected outer mar- gin and central ridge of the pterygoids into a double tube, or pterygoidean prolongation backwards of the nasal fossae, produces a corresponding elon^ gation of the palatal vault; which accordingly presents, behind its ethmoi- dal, an extensive and broad pterygoidean area, which thus completes the vault behind, as in certain Cetacea and Edentata. Among the ]\Iamm£flia the great elongation backwards of the combined maxillary palatal plates, the corresponding elongation of the combined ethmoidal neurapophyses, and the great breadth of the pterygoidean area, have displaced the palate bones so far backwards and outwards, that, separated from the ento- pterycoids and the ethmoidal neurapophyses by a wide chasm, but re- tainin'g their connections with the maxillaries and pterygoids, and coming into contact with the malar, they are, in fact, extended from the walls of the nasal fossa), and from the palatal vault, and, thus disguised, have been hitherto known only as transverse bones, adgustal bones, *' pterygoides externes, ecto-pterygoids.