694 B. W. KUNKEL 



Of recent papers which deal with the chelonian chondrocra- 

 nium especial reference should be made to that of Ogushi ('11) on 

 Trionyx japonicus in which the cartilaginous as well as the bony 

 elements of the adult skull are carefully described, and to the 

 extensive paper of Nick ('12) on Dermochelys coriacea.^ Neither 

 of these deals with the embryonic condition of the skull. Several 

 papers on the development of special regions may be referred to 

 briefly. Seydel's ('96) conclusions regarding the development 

 of the nasal capsules are confirmed, but several new facts which 

 throw light on the significance of some of the characters of this 

 region are set forth here for the first time. Noack's ('07) conclu- 

 sion that the columella arises solely from the otic capsule is 

 faulty in that my series shows the columella to be in reality made 

 up of a stapes which arises external to the capsule and an extra- 

 columella as has been described by Fuchs ('07) and Bender ('11). 

 My own results accord with those of these investigators regard- 

 ing the independence of columella and otic capsule. As to the 

 significance of the* stapes and extracolumella my results confirm 

 Bender's as opposed to Fuchs's. The latter's conclusions regard- 

 ing the development of the visceral skeleton I am able to confirm. 

 Filatoff ('06) has called attention to the presence of a processus 

 ascendens of the palatoquadratum in Emys. 



Besides these papers may be mentioned also Filatoff's ('07) on 

 the metamerism of the head of Emys, Fuchs's ('07) on the devel- 

 opment of the roof of the mouth, and Thater's ('10) on the same 

 subject. Hitherto a complete account of the embryonic chondro- 

 cranium of the turtle and its development has been lacking so that 

 comparisons have been possible only on the insecure basis- of the 

 adult condition. 



In order to obtain a clear representation of the form relation- 

 ships of the embryonic skull, a model was made by the Born wax 



' In addition to these, should be mentioned a preliminary report by P'uchs 

 (Ueber einige Ergebnisse meiner Untersuchungen iiber die Entwickelung des 

 KopfskelettesvonCheloneimbricata. Verhandl. anat. Gesellsch., 26. Versamml, 

 1912, pp. 81-106.) Unfortunately further reference to it is impossible at this 

 time. Of special importance is his demonstration of the derivation of the tropi- 

 basic skull from the platybasic type. 



