714 ALBIS: [Vou. XII. 
scheide,” while in Amphiuma it is considered by Field (No. 
33, p. 346) as the cuticula sceleti. This layer in Amia, what- 
ever its origin and character, is, with the notochord, in 30 mm. 
specimens, strongly constricted. There are, however, no 
breaks in it, as there are in Amphiuma, and no indication 
whatever of intervertebral or intercuticular cartilage, as in 
that animal. The vertebral constriction and subsequent seg- 
mentation of the notochord in Amia are, therefore, due to the 
compressive action of the cartilaginous processes, which always 
lie directly opposite and in the constrictions, and not to an 
intervertebral expansion of the notochord, as in Amphiuma 
(Field). The vertebral processes in Amia are, accordingly, in 
origin as well as in position, strictly vertebral; the dorsal 
arches, which lie between the dorsal processes and directly 
opposite the crests of the notochordal constrictions are, on 
the contrary, so far at least as their position is concerned, as 
strictly intervertebral. 
These relations do not change in 14 mm. or 12 mm. larvae. 
The dorsal processes on each side in 12 mm. larvae are, how- 
ever, found forming a continuous line, the dorsal “ Langleiste”’ 
of Goppert (No. 48, p. 168). In this line the dorsal arches 
are imbedded at their bases. The outlines of their bases 
are, however, distinctly indicated, and they lie opposite the 
places where later the crests of the notochordal constrictions 
appear. 
Whether there is also a continuous ventral line, such as 
Goppert describes, formed by the fusion of the lateral processes, 
or two such lines, one representing the line of the lateral proc- 
esses, and the other that of the ventral processes, was not 
investigated. 
From the literature at my disposal I am unable to satisfac- 
torily homologize the cartilaginous portions of the vertebrae in 
Amia with those described by others in other animals. The 
lateral processes of all, or at least most, fishes — Amia being 
especially mentioned —are called by Baur (No. 7, p. 119) para- 
pophyses, and are defined by him as the proximal, independent 
ends of the ribs or haemapophyses. What, then, are the ventral 
processes in Amia which Baur does not mention? They have 
