224 



Zoological Society, 



tilope it is assumed by every writer on the subject to be a natural 

 group, even whilst they confess that it has not a single character 

 either exclusively appropriate to it or even common to the generality 

 of its component species : far, therefore, from being a natural, it is 

 not even entitled to be considered an artificial group. The diagnosis 

 proposed by M. GeofFroy St. Hilaire regarding the nature of the core 

 of the horns, and that broached at a meeting of the Zoological So- 

 ciety by M. Agassiz, to the effect that these animals are distinguished 

 from Bos, Ovis, and Capra, by having a spiral twist of the horns 

 turning from left to right, instead of the opposite direction, are 

 founded upon hasty generalizations, inapplicable to at least three- 

 fourths of the species. 



The form or curvature of the horns, the beard, the dewlap, the 

 scopa;, the number of teats, and other such diagnoses hitherto em- 

 ployed to define the genera of Ruminants, according to the views of 

 Mr. Ogilby, are purely trivial and accidental characters, which not 

 only exercise no assignable influence on the habits or economy of 

 the animals, but which may be modified to any extent, or even 

 destroyed altogether, without in the slightest degree changing the 

 generic relations. 



Having demonstrated the imperfections of the actual distribution 

 of hollow-horned Ruminants, Mr. Ogilby proceeds to the exposition 

 of the principles which he proposes to make use of for that purpose, 

 and to explain the nature and extent of his own researches. He in- 

 sists upon the law of classification, that no generic characters should 

 be admitted but such as are founded upon the necessary relations 

 that subsist between the organic structure of animals and their 

 habits and economy. 



The next section of the monograph is devoted to the consideration 

 of the horns of the Ruminantia. Under this head the author first 

 treats of their substance ; 2ndly, their permanent or deciduous cha- 

 racter ; 3rdly, their presence or absence in different genera and sexes ; 

 and 4thly, their number, forms, and flexures. 



The distinctions between the horns of the stag tribe generally, 

 and those of the hollow-horned Ruminants, are pointed out, and in 

 the next place the various modifications observable in the horns 

 and their core of the latter group. " In some cases the substance 

 of this bony core is solid, or at least penetrated only by minute 

 pores ; in others, and they are by far the greater number, it is par- 

 tially hollow, or filled with large cancelli, which communicate with 

 the frontal sinuses. These variations are not confined to any par- 

 ticular groups, but are equally common to solid and hollow-horned 

 genera. The giraffe, for instance, has very extensive cancelli ; so 

 likewise have the oxen, sheep, goats, and all the larger species 

 hitherto classed among the antelopes : nor have I found the solid 

 core, so much insisted on by MM. Cuvier and GeofFroy St. Hilaire, 

 in any of these animals, except the A. Cervicapra, the Dorcas, and 

 their allied species." 



Speaking of the raised ridges and annuli on the horns, Mr. Ogilby 

 states that the number of these added in a given time appears to be 



