PLATES 



The outlines in plates 1, 5, and 10 were drawn from methylen-blue preparations 

 with the His embryograph and enlarged with pantograph. In finishing, certain 

 details were added from reconstruction of sections. Plates 6, 7, and 8 were drawn 

 free-hand from dissections with the camera outlines of plate 4 as the skeletal 

 basis. The outlines of all the cross-sections were made with the projection 

 lantern. 



ABBREVIATIONS 



Skeleton 



Bh 1-2, basibranchial 1-2 

 Bp, branchial plate 

 Cb 1-2, Ceratobranchial 1-2 

 Ch, ceratohyal 

 Eh 1-3, epibranchial 1-3 

 Eb*, developing new portion of first 

 epibranchial 



H, little horn 



H*, anlage, little horn 



L, lingual cartilage 



L*, anlage, lingual cartilage 



Ot, OS thyreoideum 



Muscles 



aa, adductor arcuum 



ah, abdominohyoideus 



ah*, developing abdominothyoideus 



ahs, ventral slip of abdominohyoideus 



ca 1-2, constrictores arcuum 1-2 



che, ceratohyoideus externus 



chi, ceratohyoideus internus 



da 3-4, depressores arcuum 3-4 



g, guhris 



gh, geniohyoideus 



gh I, geniohyoideus lateralis 



gh m, geniohyoideus medialis 



hg, hyoglossus 



hg*, anlage hyoglossus 



ih, interhyoideus 



ima, intermandibularis anterior 



imp, intermandibularis posterior 



la, 1-5, levatores arcuum 1-5 



Sh, sternohyoideus 



S-p, suprapeducularis 



th, thoracicohyoideus 



ths, ventral slip of thoracicohyoideus 



551 



