594 HARRIS HAWTHORNE WILDER ON 
at its dorsal prolongation, applied to the side of the neural arch. As he expresses it in 
his summary, “Die dorsale Spange ist ein verlingertes Tuberculum, das im Dienst einer 
ausgiebigeren Befestigung der Rippe steht.” Unfortunately he fails to find this dorsal 
connection in Necturus, and states that “der dorsale Theil des Quertortsatzes tritt nicht 
so deutlich als ein Balken hervor wie bei Salamandra und entbehrt auch hier der distalen 
Héhlung, da die dorsale Rippenspange den direkten Anschluss an den Querfortsatz nicht 
erreicht.” 
As shown below, and in several of my figures, this “distale Héhlung” 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 rib. Gippert’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 bearers, 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 capitular 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 they 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 table in which a few obvious abbrevia- 
tions are employed. Thus the vertebrae are expressed by consecutive numbers, begin- 
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 spines. —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, 7. e., makes the greatest angle 
