Volume 4

Monograph on the fossil Reptilia of the Wealden and Purbeck formations : supplement.

  • Richard Owen
Catalogue details

Licence: Public Domain Mark

Credit: Monograph on the fossil Reptilia of the Wealden and Purbeck formations : supplement. Source: Wellcome Collection.

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    • The monotrematous and batrachian instances show the spinous limb-weapons to be related to sex, and to be present, or fully developed, only in the males. In the class of Birds the carpal spurs are common to both sexes, but smaller in the female.^ The question remains—were the radial spines of Iguanodon common to both sexes, or developed only in one, most probably the male ? In the Maidstone specimen such appendage, with a concomitant considerable distal expansion of the radius, cannot be discerned. In the best preserved ends of the anti- brachial bones, those, viz., furthest from the humerus (as the separated fragments of the matrix, have been restored in the Maidstone specimen), the closest resemblance traceable to the more complete bones before me is at the proximal ends ; and especially, as originally detennined by me, in the ulna, or lower placed bone. In this view the distal ends, espe- cially of the radius, are partly concealed by an overlying vertebra, yet not to the extent to obscure the beginning of the radial expansion if it had existed. The shafts of both radius and ulna seem to be more slender than in Mr. Beckles’ Wealden specimen. It may be that this is of a male Iguanodon and the Maidstone specimen of a female one. A strange instrument truly in aid of the amorous embrace; yet, as in the instance of Cystignatlius, and perhaps also the Ornithorhynclius and Echidna, not without a parallel! If the radial spines, on the other hand, were developed in both sexes of the Igua- nodon, and wielded for purposes of defence by the otherwise weaponless herbivore, one cannot fail to discern in them a formidable means of transfixing an enemy—the carnivo- rous Megalosaur, e. g.—in a close death-struggle. Manus. Plate III. With the right and left anti-brachial bones and spinous appendages several bones of both the fore feet were exhumed, but not enough for a complete restoration of either foot. They give evidence that the fore-paw was pentadactyle, and that the terminal phalanges, at least of some of the toes, were short, obtuse, rough, serving for the support of horny matter in the shape of a hoof rather than of a claw. Such evidences of the carpal bones as were collected are more or less fragmentary; and, where a satisfactory union of those belonging to one and the same bone could be made, the homology of but one bone can be safely or with probability be suggested, that, viz., which answers to the large os cuneiforme in the carpus of Lizards. The proximal surface of this bone is divided into a convex and concave surface; the former was apparently adapted to the concavity of the ulnar extension of the distal part of 1 The Secretary of the Zoological Society, P. L. Sclater, Esq., F.R.S., kindly informs rae that this is the case in the pair (male and female) of the spur-winged geese (Plectropterus) now living in the Society’s Gardens.
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