OF THE TONGUE OF PAEROTS. 215 



I propose to call this muscle, which is very generally present, the ceratoglossus inferior 

 anticus accessorius (cg.i^.), and the tendon from which it arises as the uro-hypohranchial 

 tendon. 



The muscle, as a whole, does not possess a distinct tendon, but the fascia of its 

 ventral surface is somewhat tendinous and anteriorly it is confluent with the similarly 

 tendinous fascia of the lateral ceratoglossus {cg.l.). The absence of a distinct tendon, 

 is very characteristic of the more primitive forms of the muscle, and from the condition 

 of the tendinous fascia here presented up to that of a strongly developed tendon in the 

 more specialized forms there is every conceivable gradation. In Cacatwa roseicapilla the 

 muscle is like that just described, but the groove between the inner and outer portions 

 of the muscle is here represented by a considerable thinning, so that these two portions 

 are partially separated one from the other, and the thinned portion of muscle has 

 developed a thin, flat, conical tendon whose apex is attached to the root of the urohyal ; 

 and the inner portion of the muscle {cg.i.a^.) arises, not from the urohyal, but from 

 the oval cartilaginous nodule (N.) which articulates with its ventral surface. In 

 CaJyptorhynchus hcmksii and CaJyptorhynchus funereus the muscle resembles that in 

 Cacatua roseiccqnlla, but differs from it iii that the inner portion is inserted directly to 

 the urohyal, as in C. alba. In Ara araramia the muscle is fundamentally like that 

 of Cacatua alia, but the inner portion (PL XXVIII. fig. 24, cg.i.a^.) is less strongly 

 developed, inasmuch as it does not extend on to the urohyal nor meet its fellow of 

 the other side in the middle line. A ceratoglossus inferior anticus accessorius is 

 absent. 



Stage 2. 



The muscle of the five species just described is typically that kind which I propose 

 to name the unipars type; i. e., it consists only of an anterior portion, which practically 

 does not extend beyond the posterior border of the basihyal. 



In Cacatua galerita the muscle is like that in Cacatua alba, but differs from it in 

 that the inner portion (PL XXVIII. fig. 25, cg.i.a^.) is partially separated from the 

 outer [cg.i.a.) by a narrow area extended along the long axis of the muscle, in which 

 the muscular tissue is thinned, but not to quite the same extent that it is in Cacatua 

 roseicapilla ; it further differs in the splitting of the ventral tendinous fascia into an 

 inner and outer portion, which, however, still remain confluent in their anterior half, 

 and in the extension backwards along the inner surface of the hypobranchial, for about 

 the anterior fourth of the length of that, of a muscular tract (cg.i.p^.) derived from, and 

 continuous with, the outer portion {cg.i.a.) of the muscle. This small muscular tract 

 shows no signs of dividing off from the parent muscle, and it is the first definite 

 indication of the formation of a posterior portion of the muscle that reaches its 

 maximum development in the Loriidse. A glance at PL XXVIII. fig. 25 will show 

 that the tendinous fascia is elongated backwards in such a way that it appears to 



