OF THE TONGTJE OF PAEEOTS. 



217 



foreshadowed in Cacatun galerita, becomes in the higher stages evolved into a very 

 pronounced tendon. The inner portion {cg.i.a^.) of the ceratoglossus inferior anticus is 

 strongly developed, but not quite so pronounced as that in Cacatua or Calyptorhynchus, 

 nor does it, as in them, extend back to the extremity of the urohyal, but only along 

 its anterior half; it is of uniform thickness, not exhibiting any area of retrogression, 

 and its dorsal fascia also is slightly tendinous in its posterior region. 



The muscle in Cacatua leadbeateri (text-fig. 2) is fundamentally like that in Stringops, 

 but differs from it in the following details : — The ceratoglossus inferior posticus 

 extends back along the hypobranchial through the anterior two-thirds, instead of only 

 a third ; the inner portion of the ceratoglossus inferior anticus (text-fig. 2, cg.i.a^.) is 

 thin in a region (r.) in such a way that a more posterior portion {cg.i.a-.) related 



Cg-IB-i" 



eg; I. p. 



Cacatua leadbeateri. — Ceratoglossus inferior, left side, dissected away from the hyoid bone and viewed from the 

 dorsal surface, after a small portion of the ceratoglossus inferior anticus had been dissected away in 

 order to reveal the tendinous fascia of the ventral surface. (Twice nat. size.) r.= retrogressing tract of 



aj.i.a 



1. Other lettering as iu text-fig. 1. 



to the nrohyal tends to become separated from a more anterior portion (cg.i.a^.) 

 related to the basihyal, and in which the former is attached to the tendinous prolonga- 

 tion (t.) that forms the origin of the ceratoglossus inferior posticus {cg.i.p.) ; the 

 tendinous prolongation just referred to is attached to the ceratoglossus inferior posticus 

 along the inner side of its dorsal surface, and not, as in Stringops, along the middle line ; 

 that portion of the ceratoglossus inferior anticus which arises from the urohyal takes 

 its origin along the whole length of that, as in other species of Cacatua. A comparison 

 of the condition of this muscle in Cacatua leadbeateri with that on tlie left-hand side of 

 the tongue in Ptistes enjthropteriis {wfra, p. 223, PI. XXVIII. fig. 35) will show that 



