186 CEPHALOPIIUS SILVICULTOR. 



Liberia-skeleton has the first lumbar with short movable 

 ribs — apparently an individual abnormity — , the num- 

 ber however of the thoracic -|- lumbar vertebrae is 19, like 

 as a rule in all Antilopidae. On this rule however are 

 very remarkable exceptions, f. i. in our collection there is 

 a skeleton of Hippotragus eguinus with the formule 13 -J- 5 

 = 18, one of Oryx leucoryx with 13 -f- 5 = 18, in the Hunte- 

 rian Museum, London, is a skeleton of Connochaetes gmi 

 with 14 -j- 6 = 20, and in Gray's Catalogue of Bones has 

 been recorded a skeleton of Alcephalus hubalis with 13 -|- 

 5 = 18; Cuvier mentioned a Tetraceros guadricornis with 

 13 -|- 5 = 18 and Pallas a Saiga saiga with 13 -(- 5 = 18. 



The possessing of a larger or smaller number of ribs 

 is directly connected with the movableness of the vertebral 

 column, so that an animal with a smaller number of ribs 

 as a rule is quicker in its movements than its fellow having 

 a larger number; this is a remarkably important factor 

 in the economy of the individual. The study of the skele- 

 tons still is in its infancy, as the skeletons of not half 

 the number of known species of mammals f. i. have been 

 preserved. However what we know concerning the number 

 of ribs always demonstrates the above rule. 



Although there could be summed up a lot of more or 

 less important differences between the skeletons of the two 

 species, f. i. the much broader ribs in silvicultor, I think it 

 wiser to describe these skeletons not comparatively as they 

 belong to specimens of a different sex and ditto age, na- 

 mely to an adult Q Jentinki and a not fullgrown (ƒ silvicidior. 



The reason why I do not take in consideration the skeleton 

 of the very old Rotterdam-specimen and do not compare 

 it with the old Jentinki is the following. We may try to 

 imitate on the best the conditions under which an animal 

 is living in its own fatherland, the experience teaches us 

 that it is generally only a trying, more or less successful 

 indeed according to the more or less likeness or conformity 

 of what we ofler with to what the animal is accustomed. 

 And it does not matter whether an animal in confinement 



Notes from the Leyden IMuseum, Vol. XXII. 



