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Show 1874.] ANATOMY OF THE PARROTS. 595 Division 2. The ambiens muscle wanting. Subfamily (5) P Y R R H U R I N ^ E . N O further deviation. Pyrrhura. Lathamus. Coracopsis. Pyrrhulopsis. Subfamily (6) P L A T Y C E R C I N ^ E . Furcula lost. ( Platycercus. < Psephotus. { Cyanorhamphus. Psittacula. Subfamily (7) CHRYSOTIN^:. Oil-gland lost. f Chrysotis. \ Pionus. Brotogerys. In phyllogenetic language this arrangement would be expressed thus:-The original stem, in which the carotids were normally disposed, gave off a branch characterized by their abnormal arrangement. The continuation of the main stem, as well as the branch, shortly lost the ambiens muscle-the latter (and not the former), however, being represented at the present day in its unmodified form by the Arinee. Each of the two secondary branches persist as the Palaeor-nithinae and the Pyrrhurinae respectively, they both branching dichotomously in an exactly similar manner, the former giving rise to the Stringopinae and the specially modified Cacatua cristata and C. sulphurea, the other to the similarly modified Platycercinae and Chrysotinae. A method of formulation will assist in making this more readily intelligible. If the presence of two carotids, normally disposed, is represented by the figure 2, the abnormal arrangement may be represented by 2. Then, if the presence or absence of the varying structures be represented by + or -, the following Table will express the characteristics of the different subfamilies:- Paljeornithinte Stringopinas Pyrrhurinae Platycercinae T vne form «/ Sj Carotids. 2 2 L 2 2 2 2 2 2 Ambiens. + 4- Furcula. + + + + + + Oil-gland. + + + + + + The Palaeornithinse will thus be represented by the+ formula 2, - , + , + ; the Arinse by 2, + , + , + ; and so on. Plate L X X I . will represent these facts in a more self-evident manner. Through the kindness of Prof. Flower and also from the death of |