68 



STRUCTURE AND CLASSIFICATION OF BIRDS 



but a syrinx that presents some of the same characteristic 

 modifications distinguishes the stork tribe. The principal 



modification of this type of 

 syrinx is that a large number 

 of tracheal rings are altered 

 in character, in a way which 

 will be pointed out in detail 

 for one or two forms. The 

 tracheal syrinx of the Passeres 

 was investigated by JOHANNE s 

 MiJLLER, 1 but GAEROD has 

 added many new facts of 

 importance to our knowledge 

 of this kind of syrinx. 



In Hijlactes megapodius 

 there are nine tracheal rings 

 which are very much thinner 

 than their predecessors ; on 

 the anterior side, however, 

 there are twenty-three which 

 are thus altered. Two or three 

 of the anterior bronchial 

 semi-rings are modified and 

 ossified ; from the second of 

 these on each side is a ridge 

 of cartilage, the processus 

 vocalis, which extends up to 

 the twelfth tracheal ring 

 (from the bottom) . As a rule 

 these tracheophone Passeres 

 possess intrinsic muscles to 

 FIG. 47 TRACHEA OF Tantalus locu- their syringes, but the rule is 



lator. a. FROM FRONT, b. FROM . w itv.rmi- pvr>pnfinn<5 of 

 SIDE. (AFTEB GABHOD.) 11Ot wltno1 BXCept )11S, 



which Conopopliaga is one, 



as well as Hylactes, already described ; others, such as 

 Furnarius, have the intrinsic muscles. The same form of 

 syrinx seems to exist in the storks. In Tantalus loculator, 



1 In Abh. Berlin. Akad. 1845, p. 367. 



