212 PROF. W. K. PARKER ON THE STRUCTURE AND 
two papers by me which have appeared in the ‘ Transactions’ of the Royal and Linnean 
Societies, we shall be able to make rather an extended comparison of the skulls of these 
interesting types. 
But the description of the Perennibranchiate form of the Urodelous type of skull, 
which was given by Prof. Huxley a few years since in the ‘ Proceedings’ of this Society 
(P. Z.S. Mar. 17, 1874), will for ever remain a model for the morphologist to work by, 
besides supplying a fuller and more accurate nomenclature of the parts than had ever 
before been given. 
Without lessening the gratitude I feel for all the work that has been done on the 
anatomy of this group by distinguished anatomists, I nevertheless have not yet seen 
figures of the skull of the gigantic Sieboldia that have satisfied me. 
Iam therefore glad that, through the kindness of Prof. Flower (into whose hands 
the large specimen from the Society’s Gardens passed), I have been able to dissect this 
large skull myself, and to have it drawn, life-size, on stone, both from my own original 
drawings and from the real object. 
The student of these types will have full opportunity for testing the value of this 
very particular piece of work, as the skull with the rest of the skeleton will be pre- 
served in spirits in the Museum of the College of Surgeons.! 
DESCRIPTION OF THE PLATES. 
PLATE XXXVI. 
Fig. 1. Sieboldia maxima: adult. The skull, upper view: nat. size. 
Fig. 2. The same, side view: nat. size. 
Fig. 3. The same, part of mandible, inner view: nat. size. 
PLATE XXXVII. 
. Sieboldia maxima: adult. The skull, lower view: nat. size. 
. The same, end view: nat. size. 
. The same, branchial arches of right side, upper view: nat. size. 
. The same, distal part of hyoid arch of left side, upper view: nat. size. 
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PLATE XXXVIII. 
1. Menopoma alleghaniensis: adult. The skull, upper view, <2 diameters. 
2. The same, lower view, x2 diam. 
Fig. 3. The same, proximal part of mandible, inner view, x2 diam. 
4, The same, section of mandible, x2 diam. 
5. Siren lacertina: adult. The skull, upper view, x4 diam. 
Fig. 6. The same, lower view, 4 diam. 
The first dissection of this skull was made by Mr. W. Pearson, and then passed into my hands, and was 
afterwards finished by him ; this third dissection disclosed the details more perfectly than the second, by me. 
