1905.] OSTEOLOGY OF THE EURYL/EMID.^. 53 



Though I looked carefully for this slip, I failed to find it, yet I 

 examined three or four specimens. 



Foi'bes showed that, in the matter of the syrinx, the Euryla^midse 

 agree most nearly with the Philepittida^ of the Old World ; and, 

 after that, with the Cotingida?, Piprida?, and TyrannidfB of the IS'ew 

 World. This organ is of the '' Mesomyodian," " tracheo-bronchial " 

 type, or, to adopt Gadow's term, the syrinx is tracheo-bronchial 

 and " Anisomyodean." 



Had the syrinx instead of the plantar tendons been adopted as 

 the basis of classification for this group, then the Cotfngidse 

 would have been regarded as the moi-e primitive group, inasmuch 

 as in Lipciugus cineraceus the intrinsic muscle, according to 

 Beddard, is of great width, " which seems to foreshadow its 

 division in the Oscines into a complex of muscles . . . ." 



The many characters which the Euryl^midse and Cotingida? 

 share in common — skeletal, muscular, syringeal, pterylological, 

 &c. — are surely proofs that these two groups are much more neai'ly 

 allied than is generally supposed to-day : the likenesses are too 

 many and distinct to be put down to convergence or correlated 

 variation. 



The fact that the spina externa of the sternum is simple is 

 generally bracketed together with the plantar tendons, and other 

 characters, so as to emj)hasise the primitive character of the 

 Euryla^midfe. But this same peculiarity of the sternum occurs 

 again in the Cotingidae. The pterylosis of the Eurylaemidfe is 

 generally regarded as peculiar : as a matter of fact, it is hard to 

 distinguish from that of the Cotingida?. The syndactyle foot 

 again turns up — in the Cotingidse. We have already described 

 the close resemblances which obtain in the skulls of these two 

 groups. 



Turning now to the muscular system. The syringeal muscles 

 we have already referred to. They offer no striking peculiarities 

 of structure. Indeed, the only muscles which seem to call for 

 comment in this summary are the hrevis and longus divisions of 

 the deltoideus. The separation of this muscle into two distinct 

 parts is nowhere so complete as in the Passeres. 



• In its primitive (archicentric) condition, this muscle arises, in 

 part from the acromion aiid inner face of the expanded free 

 end of the clavicle and in part from the os humero-scapidare and 

 crista lateralis of the humerus. It is inserted by a common 

 tendon into the base of the ectepicondyloid process ; the tendon 

 forming the terminal of a practically homogeneous muscle. 



I have not yet had time to study the ajDOcentricities of this 

 muscle, but it would appear that as specialisation proceeds it 

 breaks up into two more or less equal and perfectly distinct 

 muscles terminating in a common tendon : later the brevis 

 portion becomes suppressed and the longus much shortened, each 

 receding farther and fai'ther up the shaft of the humerus. 



I have only just realised the potentialities of this muscle as a 

 factor in systematic work, and therefore have no large series of 



