6 



Man köiiute schließlich eine verborgene physiologische Bedeutung 

 dieser Fäden vermuten, was, wie mir scheint, durch den Zimmermann- 

 schen Befund nahe gelegt wird, auf welchen Deutungen, wie die obigen, 

 nicht wohl anwendbar erscheinen. 



Kiel, 1. Aug. 1897. 



Nachdruck verboten. 



A Preliminary Contribution to the Development of the Vertebral 

 Column and its Appendages. 



By Dr. Alvin Davison, Lafayette College, Easton, Penna, U. S. A. 



(Aus dem anatomischen Institut zu Freiburg i. B.) 



With 7 Figures. 



In the early part of May 1897 under the direction of Professor 

 WiEDERSHEiM, I began the investigation of the vertebral column of 

 Am phi urn a with the intention of setting forth additional evidence 

 relating to the recent investigations of Dr. E. Göppert in the "Fest- 

 schrift für Carl Gegenbaur". The material used consisted of four 

 adult Amphiumas and one larva 68 ram long. I will first briefly de- 

 scribe the vertebrae of the larva and then note the modification of 

 parts in transformation to the adult. The general form of the 

 vertebrae is much the same as in an embryo Amphiuma described 

 by Dr. H. H. Field in Morphologisches Jahrbuch, Bd. XXII. The 

 intravertebral constriction is less marked and the intravertebral carti- 

 laginous plates are one third thinner. The intervertebral cartilaginous 

 rings replacing the notochordal tissue extend half way to the centre. 

 The tooth-like process projecting from the first vertebra for articulation 

 with the skull has the structure of a vertebral body in that its anterior 

 termination is of the same tissue as the intercartilaginous rings and 

 its middle portion is of the characteristic hyaline cartilage on either 

 side of which is loose notochordal tissue. No ventral processes are 

 present on the bodies of the trunk vertebrae or of the first caudal 

 vertebra, but the remaining caudal elements support haemal arches 

 all of which are closed ventrally except the first three (Fig. 1). These 

 arches surround the aorta and caudal vein. 



The place of origin of the haemal arches on the vertebral bodies 

 is the same throughout the tail. The cartilage of these arches is never 

 continuous with that of the rib-carriers (Rippenträger, Fig. 1). 

 The latter are present on all the trunk vertebrae except the first and 



