394 IIARKIS HAWTHORNE WILDER ON 



at its dorsal prolongation, applied to tlie side of the neural arch. As he expresses it in 

 his summary, " Die dorsale Spange ist eiu verlangertes Tuberculuni, das ini Dienst einer 

 ausgiebigeren Befestigung der Kippe steht." Unfortunately he fails to find this dorsal 

 connection in Necturus, and states that " der dorsale Theil des Querfortsatzes tritt nielit 

 so deutlieh als ein Balken hervor wie hei Salamandra und entbehrt audi hier der distalen 

 Hohlung, da die dorsale Rippenspange den direkteu Anschluss an den Querfortsatz nicht 

 erreicht." 



As shown below, and in several of my figures, this " distale Hohlung " at the tuber- 

 cular articulation of the transverse process is often very evident, and through the 

 medium of the enclosed cartilaginous rod, articulates with the tubercular process of the 

 free i-ib. Goppert's description ('96, p. 398) of the condition in Salamandra corresponds 

 so completely with that of the adult Necturus that it could well be substituted for the 

 description given in this work. The " Abweichungen " which he finds in Necturus do not 

 exist. 



A summary of the main features of a typical vertebra and its relations to other parts 

 of the skeleton may be given as follows : — 



1. Osseous elements. Centrum; neural arch, including dorsal plate and lateral 

 laminae ; transverse process, including sheaths of rib Ijearers, and the associated dorsal 

 and ventral laminae. 



2. Cartilages and other soft parts. Two pairs of lateral rods or rib bearers; a neural 

 spine ; intervertebral notochordal cones. 



3. Articular surfaces. Two for the centrum ; two anterior and two posterior zygapo- 

 physes ; two tubercular and two capitvilar articulations for the corresponding heads of the 

 ribs. 



Comparison with Other Vertebrae. 



A study of the separate features brought out in the above description, as the}' occur 

 in the rest of the vertebral column, yields the following results. These, for the sake of 

 brevity, are expressed somewhat in the form of a taljle in which a few obvious abbrevia- 

 tions are employed. Thus the vertebrae are expressed by consecutive numbers, l:)egiu- 

 ning the enumeration with the atlas, which is 1; S is the sacral vertebra (19 or 20), 

 and H is the first one bearing a haemal arch (22 to 24) . 



Neural and haemal sjiines. — The neural spine forms a prominent ridge in 1 ; some- 

 what depressed and rounded at the end in 2. The neural spine of 3 shows the maximum 

 of size in the trunk vertebrae and is here the most erect, i e., makes the greatest angle 



