424 DAVENPORT HOOKER 
cord, if such a thing were possible. In the rest no attempt at 
apposition was made. 
Harrison (703) found difficulty in keeping ‘all sylvatica’ 
composites with a reversed middle piece alive for any great length 
of time. No more trouble was encountered in the course of the 
Fig. 1 External form of an embryo in which a portion of the spinal cord 
was reversed. A, twenty minutes after operation, the stippled area is the piece 
which has been reversed; B, twenty-four hours after operation; C, two days after 
operation; D, three days after operation; E, four days after operation; F, seven 
days after operation. A is a dorsal view, B to F lateral views. These figures 
show the peculiar spur-like process of the dorsal fin which is characteristic of 
these embryos. Outlines made with a camera lucida. (Embryo IX, 5.) 
present experiments in keeping sylvatica specimens alive than the 
other species, a circumstance which may be due to the fact that 
the piece reversed was smaller than in Harrison’s experiments. 
Where the wounds were apposed, few embryos died, but those 
animals in which fusion was not produced appear to have a lim- 
ited viability and, though many lived for weeks and became 
