56 
POSSIL REPTILIA OF THE 
In the eiglitli caudal the base of a reduced parapophysis projects from the side of the 
centrum behind its middle ; a low prezygapophysis projects from the neural arch : but 
beyond this vertebra all trace of that arch disappears, or is indicated by feeble prominences 
in the fasciculus of bone-tendons which seem to be attached to neural processes of the 
non-elongated centrums. Six or seven filamentary bone-tendons, one thicker than the 
rest, extend lengthwise above the centrum. Some of these may be traced over two 
centrums, then end in a point, their place being taken by another bone-tendon beginning 
by a similar pointed end. The parapophysis disappears in the tenth vertebra. 
The caudal vertebrae in the first discovered specimen of Diniorphodon^ answer to the 
eighth — eleventh in the present series. The elongate centrums of the tenth and succeeding 
caudals, usually more or less uncovered by the bone-tendons, show a low lateral ridge, 
and a slight expansion at the ends. The haemapophyses are traceable, much reduced in 
size, to the fifteenth — sixteenth vertebrae. The bone-tendons are in two fasciculi, one 
neural, the other haemal, in position. From five to eight may be counted in the side view 
given of each of these fascieuli. The seeming increase of thickness of some, usually the 
more peripheral of the filaments, may be due to this flattened form, and to more or less 
of the side coming into view, instead of the edge. Five or six may be counted in each 
fascicule, even beyond the twentieth caudal ; the number varying at parts through the 
formation of the bundle by successive tendons, as above mentioned. They are reduced to 
two or three at the thirtieth vertebra. The terminal joints of the elongate centrums 
appear to be flattened and closely adapted, allowing of very little motion. It is evident 
that, as in BampJiorhpichus, the tail was stiff as well as long, and doubtless served as a 
sustaining ray of the parachute of membrane continued backwards from the wings and 
hind limbs. 
The vertical diameter of the second caudal showing its neural spine is five lines. 
The diameter of the ninth vertebra, including the neural and haemal fasciculi of bone- 
tendons, is the same ; and beyond this the vertebrae and their surroundings gradually 
diminish to the pointed end of the tail. 
§ Restoration op Dimorphodon. Plate XX. 
The several parts of the skeleton of Dimorphodon preserved in the slabs of Lias 
described and referred to in the foregoing pages have ultimately yielded the desired result 
of their scrutiny and comparison, viz., a restoration of the extinct animal, such as I have 
endeavoured to exemplify in Plate XX ; and I propose to apply that plate in illustration of 
a summary of the osteology and dentition of Dimorphodon, comparing therewith the 
^ Bucklatid, loc. cit., pi. 29, a, a. I have had these vertebrae carefully redrawn, from the specimen, 
in PI. XIX, fig. 3. 
