RANGE OF VARIATION 
EXEMPLIFIED IN 
SPECIES OF DINORNIS 

HAVING given in the preceding Section details of the characters of the vertebre of 
Dinornis compared with those in Struthio, I have taken for the subject of the present 
Section the skeletons of those Moas which exemplify the extent of variation of the 
family or genus as it is shown in the gradation from slenderness to robustness of 
form. 
The species so selected are :—Dinornis gracilis (Plate CXIL. fig. 1, and Plate CXIII. 
fig. 1), D. caswarinus (Plate CXII. fig. 2), D. didiformis (Plate CXI.), D. rheides 
(Plate CIX.), and D. crassus (Plate CVIIL and Plate CXIII. fig. 2). The two extremes 
in this series are exemplified in the latter Plate. 
Under all these modifications, the essential characteristics of the osseous framework 
of the genus are retained, and the differences are due to proportion of parts, affecting 
also, in a certain degree, the shape of the bone, as in the skull and sternum. The 
chief seat of the proportional modifications, with less change of form, is the hind 
limb. 
The length of the trunk, as represented by the dorsal and sacral vertebree, retains 
a nearly constant proportion to’ the general size of the bird; it consists in all the 
species of the same number of vertebree, viz. twenty-four, of which seven are dorsal 
and seventeen sacral. The number of vertebra in the neck appears to be fifteen. J 
give these numbers as the rule or sum of my personal observations; exceptions, 
characteristic of species, may be ultimately determined; but I suspect the difference of 
one or two in the cervical series of certain mounted skeletons at Christchurch may be 
due to accident. The length of the hind limb varies in its proportion to the trunk, 
and chiefly through modifications of the tibia and metatarsus. 
Thus in Dinornis gracilis the length of these two bones exceeds that of the trunk by 
10 inches ; in D. casuarinus the excess is 8 inches; in D. didiformis and D. rheides the 
two admeasurements are equal; in D. crassus the length of the trunk exceeds that of 
the tibia and metatarsus. 
3U2 
