222 i\ru. O. p. MUDGE ON THE MYOLOGY 



the ]i()st.cnoi- margin of the basiliyal, and the ccratoglossns inferior anticus is ]jpculiar 

 in lliat its origin is from the head of the hypobranchial, as well as from the posterior 

 portion of the basihyal. In Poeocephalus rohistus the muscle is almost identical with 

 (ha( of P. rup])elli, Init tlie inner ])ortion of the ceratoglossus inferior anticus has 

 nnly reached stage II of retrogression. In Bolhorhynclms lineolatus (PI. XXIX. fig. 45) 

 tlie muscle is similar to that in I'latycercns, but the tendon of the ceratoglossus 

 inferior posticus is slightly more pronounced and to a small extent spreads out in a 

 fan-shaped form at its junction with the muscle ; the inner portion of the ceratoglossus 

 inferior anticus is also not the same, since it has only reached between stages II and III 

 in its retrogression, and tlie ceratoglossus inferior anticus accessorius (ccf.iK) is well 

 developed. In Tanj/rpiathus miXlleri the muscle is very similar to that in Bulhorhynchus, 

 except tliat the tendon of the ceratoglossus inferior posticus is not quite so strongly 

 developed; (he inner portion of the ceratoglossus inferior anticus has not reached 

 beyond stage II in retrogression, and upon the right side of the tongue it is y)rolonged 

 backwards in tlie form of a little strip on to the hypobranchial, as in PsittfPcus 

 (PI. XXVIII. fig. 29) and Ara macao. In Prioniturus sp. 1 the muscle is like that in 

 PoJhorhynclms, but the inner portion of the ceratoglossus inferior anticus lias not 

 reached beyond stage II in retrogression. 



In Pezoporus fonnosus the muscle is very specialized, and were it not that the 

 ventral fascia is still tendinous (PL XXIX. fig. 47) in its anterior portion, and that it 

 possesses a remarkably well-developed ceratoglossus inferior anticus accessoinus (cg.i\), I 

 should have placed it in the highest stage with Eos. The inner portion of the cerato- 

 glossus inferior anticus has quite disappeared. The tendon of the cerotoglossus 

 inferior posticus is very strongly developed, as strongly as that in Eos, and the muscle 

 itself is very big and divided into three portions. This division of the muscle is unique, 

 and, if we except Psittinus and Brotogerys, in which the division is of another nature, 

 does not occur in any other Parrot. The three parts into which it is divided lie 

 one above the other ventro-dorsally ; I propose to distinguish each as follows : — 

 the ceratoglossus inferior posticus ventralis (PI. XXIX. fig. 47, a), which arises from 

 the tendon at the level of the anterior head of the hypobranchial and is inserted by a 

 broad fleshy belly to the inner surface of the anterior two-thirds of the hypobranchial ; 

 the ceratoglossus inferior p)Osticus medius (PI. XXIX. fig. 47, &. text-fig. 4, y), arises 

 from the extremity of the tendon and is inserted into the posterior third of the hypo- 

 branchial ; and the ceratoglossus inferior posticus dorsalis (PL XXIX. fig. 47, & 

 text-fig. 4, /3), arises from the dorsal surface of the tendon from its posterior extremity 

 to the level of the anterior head of the hypobranchial, and is inserted along the greater 

 portion of the length of the hypobranchial. Of these, the c. i.p. medius is the stoutest 

 and is oval in transverse section ; the c. i. p. dorsalis is the longest, and is also almost as 

 stout as the " medius " ; while the c. i. p. ventralis is flat. 



In Psittinus incertus (PL XX'S^III. fig. 34) the muscle exhibits the characters of 



