178 STRUCTURE AND CLASSIFICATION OF BIRDS 



the group first concern one of the two views that we have 

 referred to above. The reasons which lead us to agree with 

 GARBOD and FORBES' s separation of a group Desmodactyli, 

 as opposed to the remaining Passeres, which are to be so- 

 called Eleutherodactyli, are as follows : The Menuridae 

 (Pseudoscines of SCLATER and FURBRINGER) are clearly in 

 some respects degenerate forms. The clavicle has become 

 rudimentary, and the muscles of the syrinx, while approach- 

 ing the typical oscinine form, where these muscles are 

 numerous and strong, have become to some degree weakened 

 by loss. 



On the other hand the Eurylsemidae, while they have 

 retained the typical mesomyodian syrinx typical, because it 



FIG. 85. SYKINX OF Eurylcemus. 

 FRONT VIEW. (AFTER FORBES.) 



FIG. 8fi. SYRINX OF Cymbi- 

 rhynchus. SIDE VIEW. (AFTER 

 FORBES.) 



is distinctive of the vast majority of birds have retained the 

 plantar vinculum, 1 which in other passerines has been lost ; 

 they have also a simple maiiubrium sterni, this appendage 

 being forked in other passerines. In the feet too the third 

 and fourth toes are largely bound together, giving to the 

 group the name of desmodactyli. 



The family Eurylaernidse 2 contains the genera Eurylamus, 

 Calyptomena, Serilopha, Psarisomus, Cory don, and Cymbi- 

 rhynchus, all Old- World. They have no aftershaft, and the 

 oil gland is, of course, nude. There are twelve rectrices in 



1 Occasionally absent in Calyptomena viridis. 



- FORBES, ' On the Syrinx and other Points in the Anatomy of the Eurylse- 

 midse,' P. Z. S. 1880, p. 380. 



