308 COPE. 
EXPLANATION OF PLATE XXIII. 
The relations of the quadrate, stapedial, and hyoid apparatus in Urodela and Sali- 
entia. Figures twice natural size, with separate details larger. 
Fic. 1. Desmognathus nigra; a, stapes separate and enlarged, the squamosal 
in place. 
Fic. 2. Salamandra maculata 2; the squamosal separated. 
Fic. 3. Diéemyctylus torosus, squamosal removed; a, separate squamosal. 
Fic. 4. Diemyctylus viridescens, three times natural size; the squamosal removed. 
2a, the squamosal, external side; 4, apex of ceratohyal, with hyoquadrate ligament. 
Fic. 5. Siren lacertina +; squamosal in place. 
Fic. 6. Discoglossus pictus, partly posterior view; @, ear bones, and origin of 
ceratohyal, enlarged. 
Fic. 7. Bufo lentiginosus americanus, the squamosal removed; a, the squamo- 
sal separate. 
Fic. 8. Scaphiopus hammondii, the squamosal removed; a, the squamosal; 4, 
the ear bones. 
Fic. 9. Ayla gratiosa, the squamosal removed; a, the squamosal; 4, the ear 
bones and cartilages in profile, the cartilages of the tympanum divided by vertical 
section; c, the ear bones and cartilages undivided, external view. 
Fic. 10. Xenopus calcaratus, partly from behind, with squamosal in place. 
Fic. 11. Stereocyclops incrassatus, squamosal in place; @, stapes and ear bones 
and cartilages. 
Fic. 12. Rana pretiosa, squamosal in place; @, ear bones and vertically divided 
cartilages, 
