OF THE TONGUE OF PAEEOTS. 227 



two-tliirds. In Cacatua galerita, C. roseicapilla, Calij'porhynchus hanJcsi, Conurus 

 jendmja, C. cactorum, C. liolochlorus, Pse^hotus, Flatycercus, P oeoceplialus rohustus, 

 Bolhorhynchus, Psittinus, Palasornis, Psittacula, Cyanorhamphus, JS'ymjjkicus, Ara 

 macao, Nestor, and Eos the muscle is confluent with the ceratoglossus inferior anticus. 

 In Cyanolyseus, Microglossus, Pyrrhura, Caica, Ptistes, Tanygnathus, Poeocephalus 

 ■rilppelli, JJeroptyus, Psittacus, Cvracopsis, Ara ararauna, and Cacatua sulphurea there 

 is an incipient division commencing, usually more marked at the posterior end. 

 In Calopsittacus, Chrysotis viridigena, C. ochrocephala, G. punamensis, Lorius fiam- 

 fallkdus, Pionopsittacus, Cacatua alba, C. leadbeateri, C. triton, Prioniturus, Strinqopts, 

 Pyrrhidopsis, Loricidus, and Vini the division of the two muscles is more or less 

 distinctly indicated in the posterior half of their common course. In Lorius domicella, 

 Pezoporus, and Eclectus the two muscles are divided, moie or less, along their whole 

 common course. In such forms as Cacatua and Striagops, where the fascia is 

 continuous and tendinous, the division is only apparent when the muscle is dissected 

 away and examined from the dorsal surface. Even then the division is not so 

 pronounced as in the other muscles with distinct tendons, and is hardly comparable 

 with them, since the fascia remains undivided. 



(c) Superior Ceratoglossal. — This muscle is exhibited in its primitive form in 

 Cacatua, Ara ararauna, CaJyptorhynchus, and Calopsittacus. In Cacatua gcderita 

 (PL XXVII. fig. 13) the muscle arises from the dorso-iuner surface of the anterior 

 half of each hypobranchial, and passing forwards and slightly inwards over the dorsal 

 surface of the basihyal, from which it also in part arises, becomes inserted into the 

 thick sheath investing a conical mass of dense connective tissue {mg^.) that lies in 

 the dorsal concavity of the entoglossum (EN.). In a large number of Parrots this 

 conical mass of tissue is either entirely replaced by muscle or by a mixture of muscle 

 and connective tissue ; and I propose to speak of it when muscular as the mesoglossus 

 muscle ymg.), and when otherwise as the mesoglossus tissue (mg^.). In Cacatua galerita 

 the two halves of the superior ceratoglossus become confluent just before reaching; 

 their insertion, and each narrows somewhat as it passes forwards from its origin. 

 In Cacatua leadbecderi, C. alba, and C. sulphurea the muscle is like that in C- galerita. 

 In C. triton the two halves each receive a small bundle of auxiliary fibres which arise 

 from the basihyal at the roots of the parahyal processes. In Calopsittacus novce- 

 hollandiw the muscle differs from that in Cacatua galerita in that its origin extends 

 farther back upon the hypobranchial, and in Coracopsis vasa, Nymphicus uuceeiisis, and 

 Psephotus xanthorrhous in that it does not extend beyond the anterior third. In 

 Ccdyptorhynclius funereus the muscle is like that in Cacatua galerita, but in Calypto- 

 rliynchus banJcsi it arises from the anterior fifth only of the hypobranchial, and from 

 the insertion of the muscle (text-fig. 5, ten.) there runs backwards a bifid tendon, each 

 fork of which extends for a short way only along the inner side of each half of the 

 muscle ; to the inner side of each of the latter there is a small muscular bundle (cg.s.a.) 

 VOL. XVI. — PAKT V. No. 3. — October, 1902. 2 l 



