258 ] 
III. On Drivornis (Part XX.): containing a Restoration of the Skeleton of Cnemiornis 
calcitrans, Ow., with remarks on its affinities in the Lamellirostral group. By 
Professor Owen, F.R.S., F.Z.S., &e. 
Read December 2nd, 1873. 
[Piates XXXYV. to XX XIX. ] 
§ 1. Introduction. 
IN a preceding Memoir! this genus of the extinct flightless birds of New Zealand was 
founded upon portions of the skeleton, including some vertebre of the neck *, the pelvis’, 
portions of the sternum ‘ indicative of the rudimental state of the keel and consequent 
incapacity of the bird for flight, a femur®, a tibia®, a metatarsus’, and a humerus*® 
described as belonging “ to some such flightless bird,” and provisionally referred to the 
species represented by the first-named bones’. 
The resemblance of the tibia in certain characters to that of a natatinal bird 
(Colymbus) was pointed out; but there were other features of the bone which checked 
the choice of the family. The minor degree of inward extension of the inner distal 
condyle (tom. cit. pl. 66. fig. 1, @), as compared with that characteristic of Anatide— 
still more the out-springing of the innear trochlear joint at the distal end of the meta- 
tarsus (tom. cit. pl. 67. fig. 1, ii, and fig. 3, iv) below the level of the interval between 
the other two trochlez, instead of the inner trochlea rising from a higher level than the 
origin of the other two trochle, together with the absence of any backward production 
of the innear trochlea beyond the plane reached by the other two trochles, were 
characters which, in the then (1865) inability to extend my comparisons of these bones 
with their homologues in the Anatide, so as to include the rare Australian form 
Cereopsis, counselled reticence as to positive statement of the Anserine affinities of 
Cnemiornis, the cranial grounds for determining the family affinities of the genus being 
wanting. 
These grounds have now been supplied by an esteemed and accomplished corre- 
spondent, James Hector, M.D., F.R.S., Government Geologist of the province of Wel- 
lington, New Zealand, from whom, in September last, I received outline figures and 
brief notes of Cnemiornis in addition to those given in my first Memoir (tom. cit.), or 
1 «On Dinornis” (Part X.) &e., Trans. Zool. Soe. vol. v. p. 395. 
2 Tb. pl. 63. figs. 1-4, pl. 64. figs. 1 & 2, 3 Pl. 64. figs. 5, 6, 7. ‘ Pl. 63. figs. 5, 6, 7, 8. 
* Tb. pl. 65. figs. 1 & 2. ® Th. pl. 66. figs. 1-5. 7 Ib. pl. 67. figs. 1-4. 
* Th, pl. 66. figs. 7-10. ° Ib. p. 396. 
VOL. IX.—ParT 1. Day, 1875. 2M 
