Zoological Society. 57 



Under-fur black ; long hair brown, upper half whitish, with a broad, 

 black, subapical band and a bay tip. Tail-end black. 



Hab. South Africa; Fort Natal. 



This species is allied to //. Mutgigella in size, appearance, and the 

 black tip of the tail, but differs from that species in being redder, and 

 in the face being red bay. 



It agrees with H . badius, A. Smith, in the colour of the end of the 

 tail ; but that species differs from it in the nearly uniform bay colour 

 and in the length of the hair. 



I may here remark, that //. badius offers two very distinct varieties, 

 one being uniform red bay, the hair being of a uniform colour ex- 

 cept a few just over the shoulder-nape which have a black subapical 

 ring. This is the variety figured by Dr. Smith in the * South African 

 Zoology.' The other with most of the hairs of the back and sides 

 having long white tips edged below with a black band, giving the 

 back a grisled appearance. 



The foregoing papers were followed by an address from Dr. Mel- 

 ville, M.H.C.S., in continuation of his observations commenced on 

 December 12, 1848, concerning the Ideal Vertebra, of which he 

 has furnished the following abstract : — 



I employ the term ' vertebra ' in the extended sense in which it is 

 used by M. Geoffroy St. Hilaire and Prof. Owen, as equivalent to a 

 segment of the endo-skeleton, or to the proximal, more or less ossi- 

 fied, element of that skeleton. 



The ideal or typical vertebra is the most complicated possible ver- 

 tebral segment, exclusive of the ichthyic or other peculiarities ; it 

 furnishes the key to the actual vertebrae in the same individual series 

 or in the skeletons of the different vertebrate classes. 



An actual vertebra may exist as a nnity prior to, or even during 

 chondrosis, but becomes resolved by ossification into a variable num- 

 ber of distinct and independent ultimate elements ; which therefore 

 are not repetitions of one and the same elementary 'body' or 

 * lamina.' 



The number of these ultimate elements varies in the actual ver- 

 tebrae in the same spinal column, and also in those constituting the 

 skeletons of the different vertebrated animals. 



The ideal vertebra contains the greatest number of these elements, 

 most of which form arches attached to, or springing from, a central 

 piece or element, and protecting the great nervous and vascular axes 

 and the visceral system. 



The upper or. neural arch is composed generally of three elements, 

 two lateral, (neural laminae, or neuropomata) ; and an upper or mesial 

 piece, (neural spine, or neuracantha), which may be subdivided in 

 the median plane. 



The inferior or haemal arch is also constituted when most developed 

 (tail of the lepidosiren) by three elements ; the two lateral (haemal 

 laminae or "angiopomata) and the azygos inferior one (angiacantha 

 or haemal spine), which is never subdivided. This arch is most 



