HORN-STRUCTURES IN THE UNGULATA. 135 



degree, to the enormous annual growth of the deer's antlers. 

 It seeaas to me that the old division of the Ruminants into 

 "Hollow-horned" and "Solid-horned" rather tends to 

 obscure the fact that the so-called " hollow " horns are not 

 really hollow, but more or less closely filled during life with 

 a bony supporting core, which is attached to the horny 

 sheath by intervening layers of membrane or skin, which 

 are full of blood-vessels, and often bleed considerably when 

 the core and its sheath are torn asunder by accidental 

 violence. 



In Owen's description the horn of the American " prong- 

 buck " is referred to as presenting in combination some of 

 the characters of the horns of the antelope, of the giraffe, 

 and of the deer ; and there is another respect in which 

 it seems intermediate between these, in that it is shed 

 periodically like the antlers of the stag ; but its horn-core 

 is not prolonged into the prong or single branch which the 

 horn gives off, but is simple like the cores of the horns 

 of the rest of the Bovidge. The horn of the prong-buck 

 may then be reckoned a true connecting link between the 

 two kinds of horns, viz, those of the oxen and those of 

 the deer. 



As this animal, the prong-buck {Antilocapra Americana), 

 differs in these and some other respects from the rest of 

 the Ruminants, iL has usually been placed by zoologists in 

 a separate section of the Ungulates, viz. the " Antilo- 

 capridse," so called because they seem to connect the 

 antelopes and goats. As correct observations of it have 

 only of late years been obtained, it may be well to 

 describe the horn-growth somewhat more in detail. The 

 horns then, which are present in both sexes, rise vertically 

 above the eyes, are flattened at the sides, and curved 

 slightly backwards at the tips. About the middle of their 



