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Show 1893.] THE ANATOMY OF PARROTS. 509 the bronchus are at first very small and do not extend across the side of the bronchus ; they gradually increase in length, until at the sixth or seventh they come to extend right across the syrinx. In Microglossa aterrima the syrinx is in certain respects less abnormal; the rings are still feeble, but on a lateral view of the organ they extend completely across, and there is on such a view no bare tract of membrane such as we have figured in Cacatua. GalyptorhyncJius banksi is intermediate between the two extremes; the first semiring only is incomplete, inasmuch as it does not reach from one side of the syrinx to the other-or rather we should say from the anterior to the posterior side. Stringops habroptilus (fig. 3) has the same weak cartilaginous bronchial semirings ; but on a lateral view of the syrinx they are seen to extend right across. b. The second group contains, so far as we can say from firsthand knowledge, the following genera :- Chrysotis. Tanygnathus. Pyrrhidopsis. Eos. Trichoglossus. Polyteles. Lorius. Platycercus. Pionus. Posocephalus. Psittacus. These genera, of several of which we have examined more than one species, are differentiated from those of the first division by the fact that the bronchial semirings are as a rule ossified and are frequently more or less fused together; at the same time the first ring is commonly concave upwards, wdiereas in the Parrots of tbe first mentioned group the bronchial semirings are straight. The most extreme type is perhaps offered by Chrysotis; of this genus we have seen the following species :- Chrysotis versicolor. erythrura. leucocephala. bodin. viridigenalis. levaillanti. In all these species (Plate X L . fig. 7) the first two rings of the bronchus are closely fused together and form a bowed piece of bone forming with the last tracheal ring a semicircular outline; the space between the two is of course occupied by membrane. In Chrgsotis levaillanti for instance, and there is no great difference in the other species, the double character of the apparently single first bronchial semiring is only to be seen at the two ends. In a number of other Parrots the first bronchial semiring is larger than that which follows though not fused with it; this is the case with Trichoglossus, Pyrrhidopsis, and Chcdcopsitta; the genera (figs. 1, 2), Polyteles, Platycercus, and Tanygnathus have syringes which are constructed on the same plan. In Conurus there is a |