1895.] Vertebral Column of Amphibia and Amniota. 259 



homologous with the visceral arches, but any attempt to homologize 

 them with, or to consider them as distal outgrowths of the inter- 

 ventralia, results in failure. Ribs and haemapophyses are not 

 homologous structures, although both are ventral arches in a general 

 sense. 



The ribs are originally attached by their capitula, to the basi- 

 ventralia ; the tubercular attachment to the neural arch is a secondary 

 acquisition. When the basiventralia are reduced, the ribs either 

 retain their old attachment and appear henceforth as " intervertebral " 

 organs, e.g., in many mammalia, in the anterior cervicals of Hatteria, 

 and in many vertebrae of Chelonia ; or they transfer their attachment 

 backwards upon the centrum, in some cases even upon the neural 

 arches. 



The spinal nerves arise originally in a transverse level behind the 

 basidorsalia and in front of the interdorsalia, i.e., intravertebrally. 

 Each nerve issues behind, or through the neural arch of the vertebra to 

 which it genetically belongs. The first spinal nerve, when it is a 

 N. sub-occipitalis (although this nerve is not in all vertebrata the 

 same serial entity) has lost its vertebra, t.he latter being added to the 

 skull, either completely, without leaving post-cranial remnants 

 (Amniota), or incompletely, and in this case the ventral arcnalia, 

 probably the interventralia only, are added to the first vertebra as an 

 odontoid -like process (JJrodda). 



XL " Spectra from Swedish Bessemer Works." By C. J. 

 LUNDSTROM. Communicated by Professor HARTLEY, F.R.S. 

 Received April 1, 1895. 



[Publication deferred.] 



XII. " Remarks on the Origin of some of the Lines and Bands 

 observed in the Spectra from Swedish Bessemer Works." 

 By W. N. HARTLEY, F.R.S., Professor of Chemistry, Royal 

 College of Science for Ireland. Received April 1, 1895. 



[Publication deferred.] 



The Society adjourned over the Long Vacation to Thursday, 

 November 21st. 



T 2 



