718 MR. W. K. PAEKER ON THE DEVELOPMENT 



T!ic next is only in the adult stage ; tins is Cijnops pyro- 

 (jaster, one of the stontest kinds, and whose skull is like the 

 skull of a Crocodile, both in the strength and ruggedncss of its 

 architecture. 



Then I have been able to follow this with a very different adult 

 skull, namely, that of a sharp-toed Japanese Newt {Onychodac- 

 tylus), which is, like the gigantic Sieboldia, a true Cryptobranch 

 or hemimetabolous type. 



After this comes the adult skull of Tariclia torosa, which is 

 almost typically Salamandrian, but falls off a little in its palatines, 

 thus leading to those that follow, in which the palatines are 

 greatly aborted, leaving the long rows of palatal teeth to attach 

 themselves to the parasphenoid, as the sphenoidal teeth. These 

 curious forms are here represented by the genera Spelerpes and 

 Besinognathus. Of the latter I have only the adult; but of 

 the former the adult of Sperlepes rubra and a larva, the 

 youngest of three larvae ; the other two being of the species 

 S. salmonea. 



'Eov details I must refer the reader to the main paper ; but 

 there are a few things that may be referred to here. 



In the adults of the lowest " Perennibranchs " certain bones 

 have appeared, namely, the premaxillaries, vomers, pterygo- 

 palatines, squamosals, frontals, parietals, and parasphenoid, besides 

 two or three on the mandibular cartilage. These also are very 

 early in their appearance in the larvse of the metabolous types ; 

 afterwards, as they begin to change, other investing bones appear :- 

 the cartilaginous roof of the nose, which is absent in the lowest 

 type, also makes its appearance, but always much later than 

 the ear-capsule cartilage. These have a new thing which the 

 Dipnoi (Ceratodus, Lepidosiren) do not possess, namely, the stapes. 

 The Urodeles borrow a very primordial submucous bone from 

 those generalized Pishes — the " pterygo-palatine," and also a 

 cartilage from the Skates and the aberrant Sharks {Notidanus) : 

 this is the" antorbital," or ethimo -palatine. 



In the Anura the " suspensorium " of the lower jaw lies so 

 close, in infancy, to the ethmoidal region of the skull, that the 

 ethmo-palatine cartilage and the pterygoid outgrowth of the sus- 

 pensorium are not developed as distinct cartilages, but are merely 

 conjugational at first. 



But in the Urodeles these parts are perfectly independent ; and 

 in them the primordial "pterygo-palatine" bony plate (in the 



