OF THE RED CRAG. 



31 



groove of the immature Zijjliii in both upper and lower jaws. But of these rudimental 

 teeth the mandibular alveolar pair, calcified and developed, in sexual or other relations, is 

 not the same in every species. Then arises the question, Is the difierence of place — in 

 one a little further forward (figs. 8 and 11), in another a little further backward (fig. 12, 

 and PI. I, fig. 4) — significant of those general or wider modifications of structure 

 which alone justify, alone make usefully applicable, a generic section of mammals 

 with its distinctive appellation? As a physiologist, or guided by common-sense, I 

 cannot admit such interpretation of value of an almost functionally insignificant character, 

 yielded by parts also which are the seat of such great and singular variability in the 

 Cetaceous order. 



Sometimes two pairs of this series of rudimental mandibular teeth are developed, as 

 in Hyperoodo7}, Lacep. In Hunter's specimen (from 30 to 40 feet long, No. 2479, 

 Mus. Coll. Chir.), as in that figured in my ' Odontography,' pi. Ixxxviii, fig. 1, i, 2, 

 the two teeth in each ramus are approximate, and the anterior one is much the 

 smallest; in Lacepede's specimen (a male, 22 feet long) they are further apart, the 

 foremost answering to the second more developed tooth in No. 2480, Mus. Coll. 

 Chir. 



In the Ziphius from New Zealand (fig. 11) two teeth are developed in the same 

 position in each ramus as in Hi/peroodon Butzkopf, Lacep. (//. Baicssardi, E. Cuv.). 

 Thereupon is proposed the genus Berardius. Duvernoy remarks — " II a, entre autres, 

 pour caractere quatre fortes dents triangulaires comprimees a I'extremite de la machoire 

 inferieure " (loc. cit., p. 41). But the term 'a I'extremite ' would apply more accurately 

 to Hunter's Ziphioid than to Arnoux's. 



As to the inadequacy of this dental character of two pairs attaining calcification and a 

 certain degree of growth, the same remark applies as to the generic importance of the 

 accident — for it can hai'dly be called otherwise — whether the fore or the hind pair of 

 such teeth rest rudimentary. 



Of any other generic characters (' entre autres') of his Berardius Duvernoy is 

 silent. 



Assuming the minor degree of symmetry in the naso-maxillary part of the skull to be 

 constant in the species, and not an individual variety, on wdiat intelligible ground can 

 such small modification of form and direction in bones, confessedly presenting in all 

 essential respects the characters of other Ziphii, sustain the imposition of a generic 

 name ? 



The intermediate step, shown by ZipJiius Arnouxii, in the development of the parts 

 of the maxillaries (fig. 11, e, e), which forms, perhaps, in its extreme degree, the best reason 

 for accepting Hyperoodon as a nominal indication of the species of Ziphioids with such 

 fully developed processes, is significant of the derivative bond uniting all the Ziphioid 

 family. 



