J. L. Bremer 461 
this embryo the closure is incomplete in the anterior part of the head, 
and also for a considerable distance from the end of the tail, giving both 
an anterior and a posterior neuropore. This is the more interesting 
when we consider that in both the pig embryo and the rabbit embryo, 
Hic. 4: Fie. 5. 
Fic. 2, 3, 4 and 5. Sections through head.  X 60. 
as described in Keibel’s Normentafeln, the closure of the medullary 
tube is completed only after the formation of the head and neck bends, 
as in this human embryo. 
