1897.] Development of the Vertebral Column. 403 
is there any modified layer of cartilage next to the elastica. 
Furthermore, when ossification begins, the layer of bone does 
not pass between the base of the arch and the elastica, but over 
the sides of the arch and against the elastica from an upper 
arch to one below it and to its fellow piece. 
For the original duplication of vertebrae Goette finds evi- 
dences in the Urodeles, lizards, ete., in what he regards as the 
occurrence of vestigial upper arches, transverse processes, and 
ribs. These, it seems to me, are as yet of too uncertain nature 
for us to base on them any such serious conclusions as does Dr. 
Goette. They are probably susceptible of being otherwise homo- 
logised. Goette has reproached the paleontologists for deriving 
their theories from their paleontological, rather than from em- 
bryological, studies. But, are the embryological materials any 
more to be relied upon to furnish safe conclusions than are the 
materials used by the paleontologist? Under the strata of 
what countless generations the primitive structures have been 
buried! How many elements that once were prominent and 
perhaps all-important have been totally suppressed, or if 
vestiges of them remain in the embryo, how difficult it is to 
detect and to interpret them! How many adaptive modifica- 
tions have been introduced into perhaps every species! Among 
the embryologists themselves there are many who declare that 
ontogony offers little reliable evidence regarding phylogeny. 
This I am not ready to admit. The paleontologist must not 
despise the embryologist ; nor must the latter scorn the former. 
We shall do well if we succeed in SAP amag nature after we 
have made use of all her aids. 
As regards the duplication of ribs, a denteies of Goette’s, one 
set for each supposed vertebral centrum, one pair must, so far 
as I see, have fallen in the intermuscular septum, the other in 
the middle ofthe myomere. The latter is a condition unknown, 
hardly conceivable. Two ribs placed at different levels in the 
same intermuscular septum might belong easily to the same 
vertebral body, as in the case of many fishes. How fortunate it 
is that the shad has not inherited a full complement of ve 
bræ and their appendages ! 
