OH, A TREATISE OX PILE. 17 



The Saki, or Cagui, (Pittecia,) is remarkable for the length of the hair on its tail, and 

 is often called, for that reason, theyb.r-tailed monkey. 



The Wistiti, or striated Monkey, (Jacchus,) has an annulated tail. 



The Marikina (Midas rosalia) has a bunch of hair at the end of the tail, like the lion. 



The Mico (Jacchus argeniatus) has a tail with deep brown hair, while that on the 

 body is silver color. 



Remarks of Tail Scales. The scales upon the tails that are prehensile are intended, no 

 doubt, to prevent them from slipping when an object is grasped. Some reptiles obtain a 

 progressive movement by means of scales. 



OF FIBROUS PROTUBERANCES RESEMBLING HORN, BUT wnicn ARE NOT TRUE HORN. 

 These processes are found upon the nose of the Rhinoceros. This animal belongs to the order 

 " pachydermata," the family "ordinary pachydermas," and forms the genus "Rhinoceros," 

 (so named from the Creek word "rin," the nose; in the genitive case "rinos," and " keras" 

 a horn.) There are two species, viz: 1, R. cornu unico conico, and 2, R. cornibus duobus 

 cuneiformibus. (Lin: 0. 5 Jumenta, No. 25, Rhinoceros.) 



This animal is large, heavy, strong-limbed and thick-skinned, nearly hairless, (a few 

 being found in the ear;) the bones of the nose, which are very stout, are united, forming 

 a vault, supporting upon its median line this solid, horn-like projection, which is uncon- 

 nected with the bone, but is buried in and adheres to the skin. It is truly said to be com- 

 posed of agglutinated fibres, which are thought to be hairs. 



Specimen of the animal in the Zoological Institute, Philadelphia, and of the horn in 

 the Academy of Natural Science, of this city. 



Fig. 10 a is a representation of a transverse section of this horn, where the ends of two 

 hairs, and a part of the third, may be seen. Fig. 10 b is a longitudinal section, showing 

 the hairs. 



Comparison with Real Horns. This (so called) horn of the Rhinoceros, will be best 

 understood by a comparison of its formation and growth with real horns, of which there 

 are the following varieties : 1. Those which are composed entirely of bony matter, and 

 2, those which are composed of an inferior osseous portion, covered -with an exterior 

 corneous matter. The first species is sub-divided into those that are perishable and 

 renewable, and those that are persistant. 



The antlers of the stag are solid and osseous, are rapidly produced by powerful blood- 

 vessels, but. after a time, they perish and fall, and are renewed in like manner. The short, 

 solid, bony processes of the cameleopard, are formed in the same manner, but they are 

 persistant. And the hollow horns of the ox, sheep, &c., are composed of two distinct 

 substances, viz : an interior one of phosphate of lime, and an exterior one of horn. These 

 two substances appear to be simultaneously produced from the two sides, respectively, of a 

 vascular membrane; and they are nourished in different modes; that of the bony interior 

 from vessels belonging to the general system, but the exterior one is destitute of vessels ; 

 and is, consequently, when once formed, removed from the influence of vital powers. 



On the other hand, the (so called) horns of the Rhinoceros, (both of the one and the two- 



