462 
PEOFESSOE OWEN ON THE DICTNODONT EEPTILIA. 
PLATE XX. 
Fig. 3. Side view, with section of tusk, of the same skull : nat. size. 
Fig. 4. Back view of the same skull. 
Fig. 5. Under view of ditto. 
PLATE XXI. 
Fig. 1. Side ■view of skull of Ptychognathus latirostris: nat. size. 
Fig. 2. Back view of Ptychognathus declivis. 
PLATE XXII. 
Picynodon tigriceps. 
Fig. 1. Side "view of skull: -g- nat. size. 
Fig. 2. Socket and base of canine tusk: nat. size. 
(II.) On the Pelvis of the DicYiiroDoisr. By Professor Owen, F.B.S. & c . 
The following description is taken from a part of the petrified skeleton of a IHcy- 
nodon equalling in size the species, D. tigricejgs, Ow., to which the cranium described in 
the preceding paper belongs, and exemplifying the structure of the pelvic part of the 
trunk of that extinct animal. 
This instructive fossil is from the same locality in the Graaf Reinet district as that 
from which the specimen of the skull of the Picynodon tigricejys was obtained which is 
described in the seventh volume of the 2nd Series of the Geological Transactions*. 
It formed the nucleus of a huge nodule of greyish-blue argillo-ferruginous hmestone, 
transmitted from that locahty by A. G. Bain, Esq., F.G.S., and is now in the British 
Museum. 
In a front view of this specimen (Plate XXIII. fig. 1) seven successive vertebrae are 
seen ; but there is an appearance of slight dislocation at the expanded and co-adapted 
articular ends of the two anterior of these (d & s i), which indicates that they were not 
anchylosed together; the rest seem to have coalesced, although traces of the interver- 
tebral articulations remain. One-half of the last vertebra (Plate XXIV. s e) is broken 
away. The length of the six entire centrums is 1 foot 2 inches. 
The first vertebra (Plate XXIII. fig. 1, d) supports a pair of long, comparatively 
slender curved ribs (^^), articulated to strong outstanding transverse processes {d). These 
were the last or hindmost pair of free ribs, and indicate great breadth in that part of 
the trunk. 
The second vertebra {fh. s i), which is the first of the sacral series, sends out a pair of 
broad and thick parapophyses {ih. ^), to each of which is attached a longer and broader 
pleurapophysis {ih. fl). This rapidly expands as it extends outwai’d, and underlaps, or 
* 4to. 1856, p. 233. 
