HEAD-MUSCLES IN GALLUS AND OTHER SAUROPSIDA. 555 



\ [-present, not mentioned by (0) or (H). 



Lacertilia vena ) 



Rhiptoglossa — the posterior part forms cerato-hyoideus of (H). 



Ophidia — hyo-glossus (H) ; it gives off the hyo-laryngeus (H). 



Mylohyoids : 



Birds — anterior mylohyoid = mylohyoideus (G). 

 posterior mylohyoid : 

 Anterior portion — serpihyoideus and stylohyoideus 



(G) ; a simple band in Lamellicostren (G). 

 Anterior constrictor colli = ceratohyoideus (G) ; not 



always developed (G). 

 Constrictor colli (G). 

 Chelonia — anterior mylohyoid = intermaxillaris (H). 

 posterior mylohyoid = constrictor colli (H). 

 Crocodilia — anterior mylohyoid =:mylohyoideus (H). 



posterior mylohyoid = sphincter colli (H). 

 Sphenodon — anterior and posterior mylohyoids form a continuous 

 sheets subcutaneous colli (0). 



[■mylohyoideus (H) and sphincter colli (H). 

 Rhiptoglossa; 



Ophidia— intermaxillaris (H) and transverso-hyoideus (H). 



List of Abbreviations employed in the Text-figures. 



ah.an. Abducens Anlage. ant. cons. colli. Anterior constrictor colli, ant. 

 carcl.v. Anterior cardinal vein, ant.mylo. Anterior mylohyoid muscle. 

 A.V. Auditory vesicle or involution, aur. Auricle of heart. IB.B. 1st 

 basibranchial. 25.2?. 2nd basibranchial. 5.fl". Basihyal. 5/t6j). Basihyo- 

 branchial plate. 1 hr.aor.ar. 1st branchial aortic arch, br.max. Branchio- 

 maxillaris muscle. Ihr.my. 1st branchial myotome. 2 6r.so?Ji. 2nd branchial 

 somite, huc.cav. Buccal cavity, cari.ento. Cartilage entoglossa. car.art. 

 Carotid artery, cer.br. 1. Ceratobranchial of 1st branchial bar. cer.hyal.c. 

 Ceratohyal bar. cer.hyal.cornu. Ceratohyal cornu. cil.g. Ciliary ganglion. 

 conj.sac. Conjunctival sac. cons.colli. Constrictor colli muscle, cr. Coro- 

 noid bone, cost.proc. Costal process, d. Dentary bone. dep.mand. 

 Depressor mandibulte. dep.imlp.inf. Depressor palpebrte inferioris. 

 dor.aor. Dorsal aorta, dor.cepli.ccel. Dorsal cephalic cojlom. E. Eye. 

 encepli. Encephalomere. epipter. Epipterygoid or processus ascendens. 

 epist.liyoid. Episterno-hyoideus muscle. extrastap. Extrastapedial. 



g.petr.ix. Ganglion petrosum of ix nerve. gass.g. Gasserian ganglion. 



