ShUKKI.DT : OSTF.C^LOGY OF THE PsiTTACI. 413 



On the under side we fiiid that the lateral processes of the leading 

 four sat ral \ertehr;v are thrown out as abutments against the nether 

 sides of the iUa ; l)eyond, or rather behind these, the usual cavity of 

 the pelvic basin occurs, and the succeeding diapophyses of these con- 

 solidated vertebrae are less manifest than common, being all elevated 

 and having their extremities in the roof above. 



The foramina for the exit of the sacral nerves are double, in each 

 case one being placed above another, and the swell to accommodate 

 the myelonic enlargement in this part of the cord's track is here well 

 pronounced. 



Conitrus, in common with many other parrots, has for its general size 

 comparatively a large sternum (Plate I, Fig. 2). Seen from above we 

 observe that the costal processes are but scarcely produced above the 

 lateral borders, which latter rise gradually to their summits. These cos- 

 tal borders each support six facets for the hsemapophyses, the concavi- 

 ties among them being pierced by small groups of pneumatic foramina. 



The space occupied by one of these costal borders is equal to about 

 half the whole length of the lateral sternal margin. (Compare the 

 sterna of Cacatiia and CalyptoHixiiiJins shown in Plate 111, l"'ig. 8 

 and Plate II, Fig. 5.) 



Posterior to them, on either side, the margins are sharp all the way 

 round the xiphoidal extremitv, this part of the bone having a shield- 

 shaped outline, being concave above, though not nearly so much so as 

 that i)art of the sternal body lying between the costal borders in front. 



In this latter section we sometimes find a few scattered pneumatic 

 foramina down the median line ; the most constant, and a large one 

 of these, however, is close up to the anterior border of the bone, 

 which curls backwards over it, and the fossa thus formed is always 

 spanned over by a median longitudinal bridge of bone. 



The anterior sternal body is thickened, and directly over its sharp- 

 ened edge in front we find a continuous coracoida! groove ; beyond 

 this there rears \\\i directly a broad quadrate manubrium, which is 

 continuous with, and has its lateral surfaces in the same plane with, 

 the carina below. 



Fxtending the entire length of the body of the bone the keel of this 

 sternum is comparatively a very deep one. Both its lower and an- 

 terior borders are convex, the latter being iiuite sharp. The carinal 

 angle formed by the meeting of these edges is roimded off. .so that the 

 lines f<?rm really one common curved line (Fig'. 2). 



