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 

 Gaebod and Forbbs's separation of a group Desmodactyh, 

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

 called Bleutherodactyli, are as follows : The Menuridss 

 (Pseudoscines of Sclatbe and Fuebeingbe) are clearly in 

 some respects degenerate forms. The clavicle has become 

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

 ing the tjrpical 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. — Syeinx of Euryleenms. 

 Front View. (Aftee Foebes.) 



FiQ. 86. — Syeinx of _^ 



rhynchus. Side View. (Aftee 



FOEEES.) 



is distinctive of the vast majority of birds— have retained the 

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

 they have also a simple manubrium 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 Eurylsemidae ^ contains the genera EurylcBTrms, 

 Galyptomena, Serilopha, Psarisomus, Corydon, and Cymhi- 

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



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



' Ooeasionally absent in Galyptomena viridis. 



' FoBBES, ' On the Syrinx and other Points in the Anatomy of the Burylee- 

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



