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THE AMERICAN NATURALIST. [Vol. XXXVII. 



9. The abortion not only of the hallux, but also of the distal 

 end of the metatarsal bone and of the phalanges of the second 

 digit of the foot, whence the foot is two-toed. 



10. The presence of thirty-five precaudal vertebrae. 



In the same place Huxley gives the following osteological 

 characters for the Ratitae, or the " struthious birds," which 

 "differ from all others in the combination" of these peculiar- 

 ities (p. 418). 



1. The sternum is devoid of a crest, and ossifies only from 

 lateral and paired centers. 



2. The long axes of the adjacent parts of the scapula and 

 coracoid are parallel or identical. The scapula has no acromial 

 process, nor has the coracoid any clavicular process ; at most 

 there are inconspicuous tubercles representing these processes. 



3. The posterior ends of the palatines and the anterior ends 

 of the pterygoids are very imperfectly, or not at all, articulated 

 with the basisphenoidal rostrum, being usually separated from 

 it and supported by the broad, cleft, hinder end of the vomer. 



4. Strong " basipterygoid " processes, arising from the body 

 of the basisphenoid and not from the rostrum, articulate with 

 facets which are situated nearer the posterior than the anterior 

 ends of the inner edges of the pterygoid bones. 



5. The upper, or proximal, articular head of the quadrate 

 bone is not divided into two distinct facets. 



In his Anatomy of Vertebrated Animals Huxley has like- 

 wise pointed out that the cervical vertebrae in the Ratitae have 

 short transverse processes and ribs, disposed very much as in 

 the Crocodilia, and I find that the ultimate vertebra of this 

 series in the ostrich bears a pair of free cervical ribs (see 

 Fig. 1). There appear to be nineteen of these cervical vertebrae, 

 and six free dorsals, the latter developing lofty neural spines 

 that gradually increase in height from before backwards. Four- 

 teen or fifteen free caudals are also found in the chain, and 

 these terminate with a stumpy pygostyle. 



The dorsal ribs and their haemapophyses are strong and 

 substantial ; the later exhibit a peculiar curving, and the epi- 

 pleural appendages of the former are aborted in subadult indi- 

 viduals. Two pairs of short pelvic ribs are seen. 



