44 
Traquair (pp. 285-6) are asymmetrical—that on the eyeless 
side having a more ventral origin and inclination; but 
the asymmetry of these processes is not specially marked 
in this vertebra, and may indeed be practically confined 
to vertebrae 5-12 inclusive. ‘The accessory rib (A.R.%) is 
attached nearer the base of the transverse process on the 
eyeless side. 
Fourth Vertebra.—Much the same as 3, except: (a) 
two moderate strengthening ridges are present on the eye- 
less side, and one on the ocular side with a deep cleft on 
each side of it; (b) a true rib is present, and is attached 
to the posterior surface of the transverse process half way 
between its extremity and the attachment of the accessory 
rib. From this vertebra onwards the transverse L-rocesses 
increase in length and the true ribs (which 1apidly in- 
crease in length up to the 7th, the longest [see fig. 18], 
but rapidly decrease in length after this) gradually 
approach the tip of the transverse process, until at about 
the 8th or 9th vertebra they are obliquely attached to the 
tip. The accessory ribs, which from the 2nd to the 9th 
inclusive vary very little in length, are also attached in a 
backwardly descending line until about the 10th or 11th 
vertebra, after which, just as they begin to decline in size, 
they rise rapidly on the vertebra (cp. fig. 18), until pos- 
terior to the 14th or lst caudal vertebra they are doubtless 
represented by the serially homologous tubercles situated 
on, and fused to, the centrum, and forming pseudo-trans- 
verse processes. 
Fifth Vertebra.—Neural spine almost flat and only 
curved backwards slightly at the lateral edges. Asym- 
metry slightly increasing. 
Sixth Vertebra.—Only one strengthening ridge on 
eyeless side and two on ocular. Asymmetry of centrum 
and transverse processes strongly marked, but more so 
