Memoirs and memoranada in anatomy / by John Cleland, John Yule Mackay [and] Robert Bruce Young.

  • Cleland, John, 1835-1924.
Date:
1889
Catalogue details

Licence: Public Domain Mark

Credit: Memoirs and memoranada in anatomy / by John Cleland, John Yule Mackay [and] Robert Bruce Young. 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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    separate joints to the back- of a pelvic structure very similar to the diamond-shaped plate of the pheasant already described, but fitting in more loosely between the right side of the sacrum and the right pelvic bone proper. As in that instance, so in this, the super- numerary pelvic structure has its ventral aspect turned to the ventral aspect of the bird; yet the two iimbs which come off from it are, the one to the right a left limb, and the one to the left a right limb. As the bones are well developed, although the muscular surroundings are feeble, there is no difficulty in determining this. On examining the viscera of this bird, it is found that, while the intestine is single, there are two pairs of ca3ca all equally developed (Fig. 6). No other abnormality was observed. The fourth specimen (Fig. 4) before me was reared by W. J. Shand Harvey, Esq., of Castle Semple, and presented to me through Mr. J. D. Dougall, of Gordon Street. It is a pheasant with a single supernumerary leg, but differs from the specimens already described, first in the pelvic bone of the supernumerary limb being quite disconnected from the pelvic bones proper, and secondly in the presence of two cloacal openings. The pelvic bone of the super- numerary limb may or may not have consisted of representations of bones of opposite sides; but the .limb which is anchylosed to it is seen by its toes to belong to the left side. With the exception of the two distal phalanges of the middle one of the three forward toes, its joints are all obliterated; but five phalanges can be coiuited on the toe to the left, and the toe to the right consists manifestly of three, therefore the limb is a left limb. I observed no trace of the inner or hinder toe. This pheasant presented the peculiarity additional to the posses- sion of a supernumerary limb, that it had two cloacal apertures, each of about normal appearance, placed side by side (Fig. 5). They opened immediately into a single dilated cavity, and there was only one pair of ureters and kidneys. But it had three CEeca, the mesial one in front of the single intestine. This contrasts with the chicken previously described, in as much as the chicken, though possessed of four cseca, could only boast a single cloaca. It will be observed that in none of the four specimens of birds which I have now described have we had to do with an appended twin. They are all instances of longitudinal fission of the posterior end of the embryo, posterior dichotomy, or what I prefer to call abcaudal fission in contradistinction to abcranial fission; and the developed limbs are in each case the right limb of the right
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