Shufeldt : Osteology of the Psittaci. 417 



for the other tendons behind. At the summit of this lione we note 

 the two condylar depressions for the trochlea; of the tibio-tarsus. 



The usual arterial foramen pierces the shaft at its ordinary site at the 

 distal end. 



As is well known, Psittaci aie jiermanently /.ygodactyle birds by 

 reversion of the fourth toe, while they not only possess a well devel- 

 oped and free accessory metatarsal, but the usual number of joints to 

 the digits. Conunis caroliiieiisis agrees in all these particulars. 



Whenever I can 1 make it a rule to fully illustrate in the figures the 

 tibio-tar.sus and skeleton of the pes, as the points presented by these 

 parts stand among the most important in this all-important system of 

 the bird's anatomy, for when sufficient data of this kind become avail- 

 able they will be not only valuable as an aid in classification, but help 

 to determine the affinities of existing birds with such fossil forms as 

 may from time to time be discovered. It will be seen that I have not 

 overlooked this fact in the plates to my original memoir on the osteology 

 of Cominis, ])ublished in the Journal of Anatomy of London. 



Synopsis of the Skeletal Characters of Conurus carolinensis. 



I. Superior mandible arched as in Raptores ; osseous nares small, 

 subcircular, separated by nasal septum. Dentary margins of mandible 

 cultrate and notched. 

 • 2. Orbital ring complete. 



3. Cranio-facial hinge as in other Psittaci. 



4. Lower margin of rostrum cultrate. 



5. Quadrate has a large and small facet on mastoidal head, a rather 

 small orbital ])rocess, and a single, longitudinal niandil)ular facet, which 

 is laterally compressed and convex in both directions. 



6. Pterygoids long and slender rods, anteriorly artic ulaling with each 

 other and with the palatines. 



7. Major portion of either palatine — a large vertical plate, directed 

 downwards and backwards. These bones curl toward each other and 

 form a limited articulation in the median line ; anteriorly they are 

 horizontally flattened, and are hingetl to the mandible beneath the 

 spongy mass, which constitutes the maxillo-palatine and nasal 

 septum. 



8. >Landil)le truncated in front ; rami and symi)hysis deep and 

 gradually rounding into each other. 



