OF GALLINACEOUS BIRDS AND TINAMOUS. 237 



The relationships of Tinamus may be put in such a form as the following, viz. : — 



Gallus. 

 Charadrius. Dendrortyx. Ocydromus. 



Syrrhaptes. Hemipodius. 



Tinamus. 

 Apteryx. Rhea. 



Casuarius. 



Mammalia : Reptilia. 



In summing up the affinities of the birds described in this paper, it may be said that 

 the " Tetraoninae " differ from the " Phasianinee," just as the Ducks differ from the 

 Geese — the legs are shorter, and the ear-drum is far more perfectly developed ; whilst, 

 as the Grouse lean towards the Sandgrouse, so the Ducks — the marine genera — lean 

 towards the Grebes and the Cormorants. 



The Curassows are evidently true and normal connecting links between the Fowls 

 and the Palamedeas. 



The Talegalla and its allies are not only related to the Curassows and Palamedeas, 

 but also to the wingless Rails, and through them to the Kagu (Rhinochetus) . 



The Hemipodii have the Quails above them, the Tinamous below, the smaller 

 Plovers on one side, and the Ground-Pigeons on the other. 



The Sandgrouse are borderers, and although lower than the Grouse in many 

 respects, being but little removed from the struthious type, yet are related, and that 

 intimately, to the Plovers and the Pigeons. 



The Tinamous are perhaps the most instructive of all these mixed forms ; for 

 although essentially struthious, yet they are structurally closely related to the Den- 

 drortyx (and through it to the Fowl), to the Hemipodius, the Syrrhaptes, the Rails, and 

 the Plovers. Finally, it has reappearing in its skull structural characters only found 

 again in such Reptilia as the Blind worms and the Skinks^ That most important bone, 

 the " OS quadratum," is thoroughly Reptilian in the Tinamou (as in the Ostriches), 

 almost single-headed in the Fowls and Grouse, and well-nigh typically ornithic in the 

 Mound-makers, Curassows, Hemipods, and Sandgrouse*. 



' Tte superorbital chain of bones occurs, as I find by a recent dissection, in the Psophia : thia bird is a 

 member of a very mixed group, yet it is one of the most intelligent of all the " Aves praecoces." 



^ At the last moment, I have received from the Gardens of the Society a fresh Variegated Tinamou (Tinamus 

 variegatus) for dissection. It differs from T. rohustus in having four sternal hsemapophyses on the left side, and 

 five on the right ; for the rest, its soft stnictures vpill yield us all that we need. The tongue is small, triangular, 

 and soft, as in the " Struthionida; ;" but its skeletal parts are of precisely the same form as in the " Galling ;" 

 yet the ceratohyals and the basihyal are not ossified, as in them, but cartilaginous, as in the Ostriches. The 

 urohyal is feebly ossified proximally ; and the thyrohyals, which are extremely delicate and long, are as much 

 ossified as in the Fowls. As in the Ostriches, the trachea is wholly cartilaginous ; in the Fowls the rings are 

 patched vpith osseous centres ; they are also feebler altogether than in the Fowls. Another extremely good non- 



