386 MR. W. A. FORBES ON THE L^^^Y 4, 



linear process, formed only by the right half of the last tracheal 

 ring, which is thus like the antepenultimate, incomplete for a part 

 of its course. The first bronchial semirings are much thickened and 

 strongly arched : they are nearly in contact in front in the middle 

 line, and are separated by but a narrow space from the last tracheal 

 ring ; behind they become incurved and thickened. The second 

 bronchial semiring is the slenderest of all ; it is shorter than the 

 first or third, and slightly concave downwards. There is the same 

 pseudo-ring formed, apparently by accumulation of tissue inside, be- 

 tween it and the first semiring as already described in Eurylceinus, 

 but it is not so apparent here. The third semiring is much longer, 

 being the longest of all the semirings, and in consequence projecting 

 at both extremities. It is nearly straight, narrow, but not so narrow 

 as the second ring, dilated behind and tapering slightly towards the 

 front. The first, second, and third semirings of each side are nearly 

 in contact with each other before and l)ehind. The fourth ring lias 

 much the same shape as the tliird, but is slightly shorter, and more 

 concave upwards than that one. The intervals between the second 

 and third and third and fourth rings are somewhat deeper than are 

 the rings themselves. The fifth and succeeding rings take on the 

 usual form of bronchial semirings, gradually becoming more com- 

 plete. As\n EurylcBinus, the single intrinsic tracheal muscle, which 

 is very slender, is inserted slightly behind the middle of the first 

 bronchial semiring. 



The EurylcEmidcB are therefore, as is evident from this description, 

 Mesomyodiani, in that respect agreeing with most of the other 

 " Formicarioid " Passeres of Wallace (Ibis, 1874, p. 406). It is 

 probable that the existence of an intrinsic muscle in the syrinx of 

 Corydon sumatranus escaped the notice of Johannes Miiller — always 

 supiJQsing that in that species the same essential form of syrinx 

 occurs as in those above described — owing to its slenderness. They 

 are wo^Tracheophone; and in that they |)ossess the sciatic, instead of 

 the femoral artery ", they differ from the Fipridce and Cotingidce, with 

 which they have so often been associated. From these, too, they 

 differ, as they do from the Tyrannida, Pittidoe, and Btipicola, in the 

 details of their syrinx as well as in the simple manubrium sterni 

 and other points. As has already been stated, they differ from all 

 the other Passeres in the retention of a vinculum in the deep 

 flexor tendons of the foot. To the general bearing of these facts 

 on the classification of the Passeres, I hope to return on some future 

 occasion. 



' Garrod, P. Z. S. 1876, p. 517. 

 - Cf. Garrod, P.Z. S. 1876, p. 616. 



