1897.] Development of the Vertebral Column. 399 
have once become distinct they never again fuse with the 
arches, and my figure represents them as being entirely dis- 
tinct. 
It is also to be noted that I disclaim holding the view that 
the intervertebral menisci of the Amniota have anything to do 
with the degenerated hypocentra. 
A considerable portion of Goette’s essay is devoted to a de- . 
fense of a publication by Dr. Ludwig Schmidt, on which I 
made some remarks. Iam unable to find anything in my 
former paper to the effect that Amia calva, being the most re- 
cent fish of the group, cannot possibly retain the embolomer- 
ous structure in case this were the older. It requires only a 
cursory perusal of that paper to discover that, after a study of 
the young of Amia, I did not regard the embolomerous condi- 
tion as more recent than the rhachitomous. I need here only 
to call attention to page 41 of that paper. 
Furthermore, I leave it to unprejudiced readers to decide 
whether or not I did Dr. Schmidt injustice when I affirmed 
that he had given two irreconcilable explanations of the way 
in which the simple vertebree of the dorsal region had resulted 
from the embolomerous condition of the tail. Schmidt's first 
effort is plainly directed toward showing that the dorsal verte- 
bre have originated through the direct union of two such disks 
-as occur in the middle of the tail. He describes and figures 
an abnormal vertebra which had been produced by the fusion 
of a “centrum” and an “intercentrum.” He figures a section 
of this vertebra and calls attention to the “ rudimentary arch ” 
of the “centrum” and to the double-cone-shaped cavity be- 
tween the two disks. Then, referring to the dorsal vertebre, 
he notes their close resemblance to the united disks of the tail, 
the presence of the rudimentary arch, and then endeavors to 
explain the absence of the notochordal cavity on the ground 
of the very early union of the elements. This is a procedure 
wholly without point, in case one of the elements has become 
wholly or almost wholly reduced. Dr. Baur had already sug- 
gested this very natural explanation, and the only fault that 
‘Schmidt found with Baur’s idea was that the latter regarded 
