174 W. BALDWIN SPENCER. 



and shows retrogressive metamorphosis, undergoing fatty 

 degeneration. What Goette regarded as the epiphysial stalk 

 is, according to Graaf, nothing more than a branch of the 

 Ramus supra-maxillaris of the fifth nerve, and always 

 terminates in the connective-tissue case, never in the organ 

 itself. The extra-cranial part, though present in the adult 

 Rana esculenta, R. temporaria, Alytes obstetricans, 

 Bombinator ingens, and Bufo cinerea, is completely 

 wanting in the full-grown Hyla arborea. In Reptilia the 

 development of the epiphysis takes place as in Amphibia, the 

 distal portion being, according to de Graaf, completely 

 cut off from the proximal stalk; it lies between the 

 brain membranes and has the form of a small, roundish, more 

 or less flattened out vesicle, and shows cellular structure. The 

 wall lying in contact with the parietal foramen is thickened and 

 lens shaped, whilst the hinder wall is pigmented on its inner side. 

 De Graaf describes in some detail and figures (PI. 4, figs. 

 32 — 34) the organ in Anguis fragilis. Reference to this 

 description will be made later on. 



Results of the present investigation. 



I desire in the first place to acknowledge the kindness of 

 Dr. Giinther, to whom I am indebted for the gift of examples 

 of difi'erent genera (indicated by an asterisk in the list below) 

 from the duplicate specimens of the British Museum; my 

 thanks are also due to Professor Stewart for the opportunity 

 of examining specimens of Iguana and Varanus from the 

 collection of the Royal College of Sui-geons. 



To E. B. Poulton, Esq., of Keble College, and to F. Beddard, 

 Esq., of the Zoological Society, I am indebted for specimens of 

 Hatteria. 



My thanks also are due to Professor Westwood for the gift 

 of a fine Chameleo vulgaris, and for the opportunity of 

 examining C. bifurcatus; and to G. C. Bourne, Esq., of New 

 College, for a specimen of Gecko mauritanicus. 



