788 RHINOCEROS-BIRDRIBS 



inhabitant of the country last named, though M. Claraz asserts (op. 

 cit 1885, p. 324) that it is occasionally found to the northward of 

 the Eio Negro, which had formerly been regarded as its limit, and, 

 moreover, that flocks of the two species commingled may be very 

 frequently seen in the district between that river and the Kio 

 Colorado. On the " pampas " E. americana is said to associate with 

 herds of deer (Cariacus campestris), and R. darwini to be the constant 

 companion of guanacos (Lama huanacus) just as in Africa the Ostrich 

 seeks the society of zebras and antelopes. As for R. macrorhyncha, 

 it was found by Forbes (Ibis, 1881, pp. 360, 361) to inhabit the 

 dry and open "sertoes" of north-eastern Brazil, a discovery the 

 more interesting since it was in that part of the country that 

 Marcgrave and Piso became acquainted with a bird of this kind, 

 though the existence of any species of Rhea in the district had been 

 long overlooked by or unknown to succeeding travellers. 1 



RHINOCEROS-BIRD, an old book-name for one or more of 

 the HORNBILLS (p. 433), and occasionally used by modern South- 

 African travellers for the OX-PECKER (p. 680). 



RIBS, if typically developed, have a double attachment to the 

 vertebrae a capitulum or " head " articulating with the centrum of 

 a vertebra, and a tuberculum or knob movably applied to the trans- 

 verse process of the same vertebra. The portion next to the 

 " head " is known as the " neck," and to it succeeds the shaft, 

 composed of two pieces, the dorsal or vertebral (to the posterior 

 margin of which is generally attached an UNCINATE PROCESS) and 

 the ventral, which is sometimes called the sternal or sterno-costal 

 rib. If this ventral piece reaches and articulates with the sternum, 

 the whole is called a " true " Rib ; but if the sternum is not reached, 

 the whole is called a "false" Rib, even if the ventral piece be 

 present. 



According to their position Ribs are usually distinguished as 

 (1) Cervical Ribs possessing only a short shaft, while both head and 

 tubercle are immovably fused with the vertebra ; (2) Cervico-dorsal 

 Ribs movably attached to the vertebrae, being in number from 1 to 

 4 on each side, with a shortened shaft which may in some cases 

 carry a small ventral piece; (3) Thoracic Ribs, connecting the 

 vertebral column with the sternum, from 3 to 9 in number as 



1 Beside the works above named and those of other recognized authorities 

 on the ornithology of South America such as Azara, Prince Max of "Wied, Prof. 

 Burmeister and others, more or less valuable information on the subject is to be 

 found in Darwin's Voyage ; Dr. Booking's " Monographic des Nandu" in (Wieg- 

 mann's) Archivfur Naturgeschichte (1863, i. pp. 213-241) ; Prof. R. 0. Cunning- 

 ham's Natural History of the Strait of Magellan and paper in the Zoological 

 Society's Proceedings for 1871 (pp. 105-110), as well as Dr. Gadow's still more 

 important anatomical contributions in the same journal for 1885 (pp. 308 et seqq.} 



