1868.] PROF. HUXLKY ON THE ALECTOROMORPH.E. 303 



pterygoid and tlie basipterygoid processes, on the other hand, are 

 like those of the PeristeromorphcE, 



3. The sternum and furcula, as well as the coracoid (in its short- 

 ness, breadth, and the presence of a subclavicular process), are com- 

 pletely Peristeromorphic ; and so is the whole fore limb. 



4. The pelvis has resemblances both to that of the Grouse and 

 that of the Pigeons, but has some peculiarities of its own. 



5. The foot contrasts strongly with that of the Pigeons in the 

 extreme brevity of the tarso-raetatarsus and toes, and in the reduc- 

 tion of the hallux, but may be regarded as an exaggeration of that 

 of the Grouse. 



According to Nitzsch, the pterylosis is Peristeromorphic ; and 

 •Mr. Parker {I. c. p. 150) has shown that while the vocal organs are 

 Pigeon-like, the digestive organs are Tetraonine. 



Thus the PteroclidcB are completely intermediate between the 

 AlectoremorphcB and the Peristeromorphce* . They cannot be in- 

 cluded within either of these groups without destroying its defini- 

 tion, while they are perfectly definable in themselves. Hence, I 

 think, the only advisable course is to make them into a group by 

 themselves, of equal value with the other two, under the head of 

 Pferoclomorphce. 



The Hemipodiclce differ much more from the Alectoromorphcp, 

 PterocJomorphw, and Peristeromorphcc than these groups do from 

 one another. 



1. The number of the cervical, dorsal, and lumbar vertebrae is 

 indeed the same ; but that ankylosis which is so constant and so 

 remarkable among the birds which have been already mentioned is 

 absent. All the vertebrae are distinct from one another, as Mr. 

 Parker has already noticed (J. c. p. 184). 



2. The palatines, pterygoids, and basipterygoids are more Plu- 

 vialine, though there is a touch of the Pigeon both in these parts 

 and in the mandible. They are very different from the correspond- 

 ing bones in the AlectoromorphcB and PteroclomorphcB. The broad 

 flat vomer, however, is not Pluvialine, but is more Grouse-like. 



3. The sternum appears to me to be, as nearly as may be, in- 

 termediate between that of the P teroclomorphce and that of the 

 Tinamorphce. If the inner notch, which is already so small in Sijr- 

 rhnptes, were reduced to nothing, the sternum would differ from 

 that of Hemipodius in very little but the breadth of its middle 

 xiphial process. In fact, it seems to me to he demonstrable that 

 the long xiphial process of the sternum of Hemipodius answers to 

 the outer of the two metosteal processes of the AlectoromorphcB, — and 

 not to the inner, as Mr. Parker supposes in his ])aper on the Galli- 

 naceous birds — or to the inner and outer together, as he suggests in 



* M. Blanchard excludes Ptcrocks from the " Gallinaces," and exjjresses, 

 " without the least doubt," the opinion that this genus should be ranged among 

 the Pigeons. " La forme de leur sternum, de lem- bassin, de leiu's menibres an- 

 terieurs, de leur humerus notamment, ne pent laisser a cet egard la moindre 

 incertitude" (Blanchard, I. c. p. 9.3). M. Blanchard does not mention Hemipo- 

 dius, and is uncertain about the affinities of Tinamus. 



