410 Annals of the Carnegie Museum. 



0/ the Hyoid Arches. — Notwithstanding the fact that the glosso- 

 hyal which su])port.s the thick, short and fleshy tongue of this Parrot 

 remains in cartilage throughout life, the ceratohyals are very completely 

 developed. They meet in the median line, and ossify up to the very 

 hinder body of this element and anterior to them. Where they unite 

 at the mesial point behind, an articular surface is formed for the first 

 basibranchial. This last named element is unusually long, and anchy- 

 loses with the second basibranchial, the i)oint of mergence being en- 

 larged to accommodate the heads of ceratobranchials and anteriorly to 

 support a peculiar osseous outgrowth that, .so far I am at present in- 

 formed, is restricted to the Psittaci ; indeed, this is the only form in 

 which I have observed this latter feature. 



The ceratobranchials are very long, subcylindrical and rather stout 

 rods of bone, while, on the other hand, the epibranchials are notably 

 short and but feebly developed. As thus constituted, the thyrohyal 

 elements show but little curvature along their continuities, and still less 

 disposition to curl up behind the cranium. 



Of the Remainder of the Axial Skeleton. — Coiiiiriis carolinensis has 

 thirty-five vertebra; in its spinal column, and a large pygostyle at its 

 terminal extremity. This agrees with Cacatita galerita. (See PI. 

 III. ) The atlas is characterized by a broad neural arch above, a 

 perforated cup for the occipital condyle, and a prominent process 

 extending backwards from the pseudo-centrum behind. 



Axis vertebra has a very inconspicuous odontoid process, strongly 

 developed neural and hypapophysial spines, and tuberous jiostzygapo- 

 physes. This segment, like the rest of the column and the pelvis, is 

 pneumatic ; to this statement, however, the last five caudal vertebrae 

 and pygostyle prove an exception. 



Both third and fourth vertebrae have strong h)'pa]:)ophysial spines, 

 and neural ones scarcely less marked. In these, too, the lateral canals 

 are seen, but the processes at their hinder margins are, as yet, but 

 feebly produced. The zygapophysial arms are short, and their being 

 joined from before backwards in each case by bone extension lend to 

 these two segments a 'width upon their dorsal aspects and a solid ap- 

 pearance not possessed by any of the other vertebrae posterior to them. 

 In the fifth vertebra, the dorsal and ventral spines have lost not a 

 little of their prominence, while the parapophyses are much longer. 

 This segment has the postzygapophyses manifestly lengthened, A\hereas 

 but little change has taken place in the anterior })air. 



