4 
788 RHINOCEROS-BIRD—RIBS 
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 Rio 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 Rio 
Colorado. On the “pampas” #. 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 &. macrorhyncha, 
it was found by Forbes (Jbis, 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. 
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 
vertebra—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 vertebra, 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. Bécking’s ‘‘ Monographie des Nandu” in (Wieg- 
mann’s) Archiv fiir Naturgeschichte (1863, i, pp. 2138-241) ; Prof. R. O. 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.) 
| 
