226 MK. G. P. MUDGE ON THE MYOLOGY 



Stage 9. 



This stage differs from the hist only by the niaiked miiniier in which the posterior 

 end of the tendon spreads out in a fan-shaped form (PI. XXIX. fig. 39) over the 

 anterior half of the ceratoglossus inferior posticus. 



Uos riciniata is the only one of the Parrots examined that exhibits this particular 

 character developed to the same extent. The ceratoglossus inferior anticus is merged 

 with the lateral ceratoglossus along its whole length, except where the uro-hypobranchial 

 tendon passes between them to its attachment at the basihyal ; its inner portion has 

 completely retrogressed (= III). The ceratoglossus inferior posticus is like that in 

 Lorius flavo-])alliatus. 



(b) Lateral Ceyatoglossal. — This muscle arises fleshy from the dorso-lateral surface 

 of the hypobranchial and is inserted by a tendinous insertion, common to it and the 

 inferior ceratoglossal, to the anterior lateral process of the os entoglossum. In some 

 cases its origin posteriorly is from the dorsal surface of the hypobranchial, and it 

 gradually shifts, as it runs forwards, to the lateral surface. The chief differences 

 which it exhibits are concerned with the amount of its extension along the hypo- 

 branchial, in its confluence or separation from the ceratoglossus inferior anticus, and 

 in the nature of its tendon, i. e., as to wliether it is a distinct tendon or merely a 

 tendinous fascia. With respect to the last character, the tendon varies in precisely 

 the same way and in correlation with that of the inferior ceratoglossal, being a distinct 

 tendon when that of the latter is so, and of the nature of a tendinous fascia otherwise ; 

 in the cases where it is of the latter description, the two muscles are covered by a 

 single fascia, and the tendon of the lateral ceratoglossal, like that of the inferior 

 ceratoglossal, is evolved as a thickened tract, the progress of its evolution keeping pace 

 with that of the latter muscle. 



In Cacatua alia, C. leadheateri, and Calyptorliynchus funereus tlie muscle extends 

 backwards along the anterior third of the hypobranchial ; in the last-named Parrot it 

 is slightly more than this. In Ara, Cyanolyseus, Cacatua triton, C. sulphurea, C. rosei- 

 (rqnlla, C. galerita (PI. XXVIII. fig. 25), Calijptorhynchus banksi, iJeroptyus, Micro- 

 glossus, Kasiterna, JVestor, Psittacus (PI. XXVIII. fig. 29), Psittacula, Pseijliotas, 

 Poeocejyhalus rohustus, and Stringops (Pi. XX VIII. fig. 26) it extends along the 

 anterior half. In Coracopsis, Chrysotis panamensls (PI. XXVII. fig. 14), C. cestiva, 

 C. viridigena, Calopsittacus, Posocejjhalus riippeUi, Tanygnathus, Nymphicus, Conunis 

 cactorum, Brotogerys, Falceornis (PI. XXVIII. fig. 32), Pyrrhulopnis, and Loriculus 

 it extends along the anterior two-thirds. In Psittinus, Chrysotis ochrocepliala 

 (PL XXVIII. fig. 28), and Pionopjsittacua it is just slightly more. In Lorius 

 (PL XXIX. fig. 37), Eos (PL XXIX. fig. 39), Vini, Cyanorhamphus, Prioniturus, 

 Conuras holochlorics, C. jendaya, Pyrrhura, Caica, Pezoporus, Ptistes, Bolhorhynchus, 

 Platycercus, and Eclectus it extends to or near the posterior extremity of the bone. 

 In Platycercus and Eclectus the muscle turns to the dorsal surface in its posterior 



