238 Mil. G. P. MUDGE ON THE MYOLOGY 



Method C. 



Stage 1. 



In Brotogerys pyrrhopterus (text-fig. 9) there is but a single muscle to represent both 

 the thyroglossus and thyrohyoideus. It has a double origin, in part from the inner 

 surface of the posterior half of the entoglossum (E.N.) (= origin of thyroglossus in 

 certain other Parrots) and in part from the inturned apical portion of the parahyal 



Brotogerys jiyrrJiopierm. — Dorsal view of thyrohyoideus. (Twice nat. size.) 

 E.N. = entoglossum. 

 P.P. = parahyal process. 

 th.h. = thyrohyoideus. 

 mg'. = tissue identified as mesoglossus. 



T. = trachea. 

 ih.g. = the forward prolongation of th.h., and which in other 

 Parrots becomes separated as the thyroglossus. 



process (P.P.) (= origin of thyrohyoideus in all Parrots). Its insertion is upon the 

 dorso-lateral surface of the thyroid. The muscle of either side is confluent with its 

 fellow in the middle line in front of the glottis. 



In Conurus cactorum the condition of the muscle is similar to that in Brotogerys, 

 except that the insertion extends ventrally on to the ventro-lateral surface of the 

 thyroid ; the representation of the muscle for Comirus jendaya fPl. XXVI. tig. 9) 

 would do for C. cactorum if the plane of division there indicated between the thyro- 

 glossus and thyrohyoideus were not present. 



