212 PEOF. 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. 



AVithout lessening the gratitude I feel for all the work tliat 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 Sieholdia that have satisfied me. 



I am 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 

 di-awings 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. i 



DESCRIPTION OF THE PLATES. 



PLATE XXXVI. 



Fig. 1. Siebohlia 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. 



Fig. 1. Sieloldia maxima : adult. The skull, lower view: nat. size. 



Fig. 2. The same, end view : nat. size. 



Kg. 3. The same, branchial arches of right side, upper view: nat. size. 



Fig. 4. The same, distal part of hyoid arch of left side, upper view : nat. size. 



PLATE XXXVIIL 



Fig. 1. Menopoma alJeghaniensis: adult. The skull, upper view, x2 diameters. 



Fig. 2. The same, lower view, x2 diam. 



Fig. 3. The same, proximal part of mandible, inner view, X 2 diam. 



l^ig. 4. The same, section of mandible, X 2 diam. 



Fig. 5. Siren lace rtina: adult. The skull, upper view, x4i diam. 



Fig. 6. The same, lower view, x4 diam. 



' Tlic_;?cs( dissection of this skull -n-as made by Mr. W. Pearson, and then passed into my hands, and was 

 afterwards finished by him ; this third dissection disclosed the details more i>crt'ectly than the second, by me. 



