THE STRUCTURE OF MAN 



the assumption of the former presence of "proto- vertebrae" 

 [or mesoblastic somites] in this region, and these, in turn, might 

 indicate the prolongation of the spinal 

 cord into the caudal region in earlier 

 embryonic stages (cf. Fig. 20). 



We must not, however, assume, as 

 Gerlach justly observes, that a true 

 tail, supported by skeletal tissues, 

 would have developed in this embryo 

 had it lived longer ; because the 

 tissues lying in the region of the 

 caudal filament showed no traces of 

 conversion into permanent cartila- 

 ginous or osseous vertebrae. It was 

 further observed, that at the point of 

 junction between the posterior coccy- 

 geal vertebra and the proximal end 

 of the caudal filament, the chorda dor- 

 salis had already disappeared. These 

 FIG. IS.-TAILED^HUMAN EMBRYO. factg indicate an attempt to return 



to the normal. The tail showed every 



sign of degeneration ; but this does not detract from the great 

 morphological interest of the case, which has led me to describe 

 it at some length. 



Three other certified cases of tail formation in human beings 

 may be cited. 



The first is that of an Esthonian recruit, described by Max 

 Braun in vol. iv. of the Zoologischer Anzeiger. The coccyx, in 

 this case, did not recede into the groove of the buttocks under 

 cover of the nates, but ended in an eminence, which, though not 

 long, could be laid hold of and felt by the fingers. Thus exa- 

 mined, it was found to lie in a direct line with the vertebral 

 column and to contain distinct vertebras, the last of which was 

 about the size of a pea. It could not be certainly ascertained 

 in the living subject whether this tail was due to numerical 

 increase in the number of vertebras, or simply to a retention of 

 the embryonic straight condition of the coccyx itself. It is a 

 noteworthy fact, however, that Ecker's glabella and foveola 

 coccygea, or sacral dimple, had persisted. 



The second case is that of a newly-born female child, recorded 

 by Lissner in 1872. Here also hard, irregular bodies, somewhat 

 like the phalanges of a finger, could be distinctly felt in direct 



