594 MR. A. H. GARROD ON THE [Nov. 3, 



never, as it happens, both together) have further aided in the forma- 

 tion of tertiary and further subdivisions, which, upon the dissections 

 above given, would lead to the arrangement of the family which is 

 depicted in Plate LXX. 



This may be represented in the tabular form as follows : — 

 Suborder (or Cohort) PSITTACI. 



Family I. Pal^eornithid^. (Left carotid normal.) 



The ambiens muscle absent. Carotids two, except in the genus 

 Cacatua. 



Subfamily (1) Pal^ornithin^;. No further deviation. 

 PalcEornis. 

 Eclectus. 

 Aprosmictus. 

 Tanygnathus. 

 Prioniturus. 

 Psittinus. 

 Loriculus. 

 Trichoglossus. 

 Lorius. 

 Eos. 



Subfamily (2) Cacatuin^. Orbital ring completely ossified, 

 and characteristic in that it develops a process bridging 

 the temporal fossa (vide Plate LXXl.). 

 Calopsitta. 

 Calyptorhynchus. 



{Licmetis. 

 Eolophus. 

 Cacatua. 



Subfamily (3) Stringopin^e. The furcula lost *. 

 Stringops. 



(Euphema. 

 Geopsiitacus. 

 Melopsittacus. 

 Agapornis. 



Family II. Psittacid^e. (Left carotid superficial.) 

 Division 1. The ambiens muscle present. 



Subfamily (4) Arin^. No further deviation. 

 Ara. 

 Comoros. 

 Bolborhynchus. 

 % Ca'ica. 

 Psittacus. 

 Pyocephalus. 

 Nestor. 

 * See the special remarks on this group in the postscript to this paper. 



