262 ME. G. P. MUDGE OIS THE MrOLOGT 



and a posterior one. In Conurus jendaya and Cacatua grderita the anterior portion 

 is very indistinctly divided into two. 



In Lorius domiceUa (text-fig. 12), Fini, Prionitarus, Chr/jsotis, Ptistes, Xr/siterna, 

 Jiolhorhynclms, Loriculus, Pyrrhnra, Brotogerys (text-fig. 13), PaUeornis, Platycercus, 

 and Tanygnathus the posterior division of the muscle arises from the ventral margin 

 of the rami of the mandible. In Lorius flavo-palliatus (text-fig. 14), Conurus jendaya 

 (text-fig. 10), Eos, Stringops, Pezoporus, Poeocephalus, Ara, Psittacus (PL XXVI. 

 fig. 3), Psittacula, Eclectus, Cyanolyseus, Coracopsis, and Cacatua it arises from the 

 outer surface of the rami. 



In Nestor notahilis the muscle consists of two divisions only, but they become 

 confluent at their insertion (PI. XXIX. fig. 46), and form a tubular investment round 

 the extremity of the hypobranchial and the whole length of the ceratobranchial. 



The Genioglossus Muscle. 



This is a paired muscle arising from the inner surface of the posterior end of the 

 lower bill, immediately on either side of the middle line. Each half passes upwards 

 and forwards, and becomes inserted (PL XXIX. fig. 50, gg.) into a thin ridge which marks 

 the dorsal limit of the posterior lateral process of the entoglossum (cf. P. Z. S. 1895, 

 p. 166). It has fundamentally the same arrangement in all Parrots, except Nestor, in 

 which the two portions of the muscle pass dorsally to the entoglossum and become 

 confluent with each other in the middle line, so that there is no insertion to the ento- 

 glossum ; the muscle merely forms a loop round it. 



The Ceratohtoideus Muscle. 



This muscle exhibits but little variation. Its origin in some instances (PL XXVIII. 

 fig. 28) is entirely from the sheath investing the urohyal; in others it is partly from 

 that and partly from the posterior border of the uro-hypobranchial tendon ; and in a 

 few (PL XXVIII. fig. 24) it is partly from the nodule (N.) on the ventral surface of the 

 urohyal and partly from the uro-hypobranchial tendon (u.ten.). Its insertion in all 

 cases is into the inner surface of the hypobranchial, ventrad of the origin of the 

 ceratoglossus inferior posticus, sometimes towards its anterior and at others towards 

 its posterior end. 



In Microglossus, Tanygnathus, Pyrrhulopsis, Platycercus, PoeocepliaJus ruppelli, 

 Cacatua, Nestor, Psittacus, Psephotus, Conurus holochlorus, Coracopsis, and Brotogerys 

 (PL XXVIII. fig. 33, cli.) it arises entirely from the urohyal sheath. In Calyptorhynchus, 

 Palceornis, Loriculus, Eclectus, Bolborhynchus, Psittacula, Nasiterna, Cyanorhamphus, 

 Pyrrhura, Pionopsittacus, Ptistes, Psittinus, Conurus jendaya, C. cactorum, Pezoporus, 

 Cyanolyseus, Stringops, Calopsittacus, and Prionitunis it arises partly from the urohyal 



