INTRODUCTION. хіх 
trachea does not, as in the Oscines and several other Passeres, form a three-way piece, 
because there is no antero-posterior bar traversing its inferior margin in the middle line. 
Of this, however, there is an indication in the form of a median backward-directed process, 
which advances a short distance into the inferior membraniform completion of the tube 
from its anterior border. The tracheal ring last but one is complete, and has a slight 
median indentation in its inferior margin behind. The first and second bronchial rings are 
semi-rings, not modified into the somewhat separate round-margined, slightly oblique semi- 
circles of fibro-cartilage or bone which, as usual, are found near the lungs, but are like 
moieties of true tracheal rings, approximate, sharp-edged, and at right angles to the axis of 
the tube. They present no peculiar processes, and are slightly swollen at their anterior 
extremities. | 
There is only a single pair of bronchial muscles continued down from the sides of the 
wind-pipe, insignificant in size, quite lateral, and terminating by being inserted into the 
middle of the outer surface of the second bronchial semi-ring. 
PITTA GUAIANA differs only in detail, not in plan of conformation. There are four 
instead of two syringeal bronchial semi-rings, to the middle of the last of which the single 
extremely feeble lateral muscle is attached on each side. In it also the last two tracheal 
rings, and not the last only, are incomplete behind, the last presenting a greater gap than 
the one above it. In a previous paper on the “ Carotid Arteries of Birds,” the same 
writer (Proc. Zool. Soc. 1873, p. 457) has shown that Pitta possessed only the left 
carotid. 
According to the evidence given above, the Pitta belong to what Garrod terms the 
Haploophone division of the Mesomyodian Passeres, and should be placed with those birds 
which have the museles of the syrinx joined to the semi-rings in their middles. Forbes 
(Proc. Zool. Soc. 1880, p. 391), on account of these Mesomyodian groups differing from 
the Eurylæmidæ in having lost the plantar vinculum, and by having the manubrium sterni 
strongly forked, has placed them in a separate main division called Eleutherodactyli. Тһе 
main artery of the leg is the sciatic, not the femoral, and the Pitta have the planta 
bilaminate, in this latter respect agreeing with the Acromyodian Passeres. Other points of 
their anatomy are the nude oil-gland, the coli cæca being one-eighth and one-tenth of an 
inch in length, the absence of the ambiens muscle, and the independence of the flexor 
longus hallucis from the flexor digitorum perforans. А peculiarity of the skull, at least 
among Passerine birds, is the extension of the temporal fossæ across the occipital region 
so as nearly to meet in the centre. The sternum of Prrra GUAIANA has the sternal 
notches very deep. 
Prof. W. K. Parker, in his memoir on Ægithognathous Birds (Trans. Zool. Soc. vol. ix. 
1873, p. 314, pl. 57), has described and figured the palate of Pitta melanocephala, ex 
Borneo (P. вокртрл, Müll), and compared it with Thamnophilus doliatus, and among 
other important distinctions states that the “ intimate union of the vomer with the nasal 
capsule " puts Pitta into the typical division, and in this respect has complete 
f 
