188 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



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. 3 ) 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 ; (6) 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 processes 

 increase in length and the true ribs (which rapidly 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 1st 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. Asymmetrv of centrum 

 and transverse processes strongly marked, but more so 



