ORIGIN AND SIGNIFICANCE OF SPINES 59 



height and prominence of the horns on the Giraffe, or are 

 even relatively more pronounced. 



The males of some other vertebrates have spiniform processes 

 or spurs on their legs and wings serving particular functions. 

 The spurs in birds are to be considered mainly as weapons 

 which are used by the males in combats among themselves. 

 They are developed on the metatarsal or metacarpal bones as 

 bony processes ensheathed in horn. In the females the 

 spurs are generally rudimentary. A kind of spur is also 

 found on the hind limbs of the male Echidna and Ornitho- 

 rht/nchus, attached to the astragalus. It is perforated by a 

 duct leading from a gland. The functions of the spur and of 

 the secretion are unknown. 



Many lizards, especially among the Chamseleontidse, present 

 striking differences between the sexes, and the males of some 

 of them develop veritable horns like those in cattle, sheep, 

 and other hollow-horned ruminants. Darwin^* illustrates 

 and describes a number of most interesting examples. One 

 of them Chamceleon Oweni is here shown (figures 45, 46). 

 The male has three horns, one on the snout and two on the 

 forehead. They are supported by bony excrescences from 

 the skull. From tlie peaceable nature of these animals, 

 Darwin concludes that " we are driven to infer that these 

 almost monstrous deviations of structure serve as masculine 

 ornaments." 



The males of the tropical American genus of fishes Cal- 

 lichthys "have the spines on the pectoral fins stronger and 

 longer than tliose of the female, the spine increasing in size 

 as the male reaches maturity" (Seeley^^). 



Among insects the males of many beetles belonging to the 

 lamellicorns have long horns arising from various parts of 

 the head and thorax. One of the best known forms is the 

 Hercules beetle Dynastes Jiercules. Bateson^ states that, in 

 this and other genera, it is commonly found that the males 

 are not all alike; but some are of about the size of the 

 females and have little or no development of horns, while 

 others are more than twice the size of the females and have 



