284 



F. H. EDGEWORTH, 



aud Teleostomi that possibly the only coniinon feature is the 

 above-mentioned first stage. In Ceratodus, Sauropsida, and 

 rabbit the h^^oid myotome is external to the upper part of the 

 hj^oid bar, as in Scylliuni. 



In Sauropsida and certain Teleostomi ihe adductor man- 

 dibnlffi divides into internal and external portions, but in 

 Teleostomi there is no uniform upgrowth of the external 



Text-fig. 85. 



Text-figs. 85-87.— Rabbit, embryo 5 mm. ; Text-fig. 85 is through 

 the first In-anchial segment. Text-fig. 86 through the third 

 branchiiil segment. Text-fig. 87 just behind this. 



portion to the skull as in Sauropsida. Both division and 

 upgrowth have been independent occurrences in these two 

 phyh). 



C. Amongst the animals investigated there are but few in 

 which muscle-Anlagen are developed and then atrophy. The 

 Mm. marginales and interarcuales venti-ales of the larva of 

 Rana, certain muscles of metamorphosing Urodela described 

 by Driiner, the levator maxillee superioris of Chelone and 



