MICHIGAN ACADEMY OF SCIENCE. 
105 
a male for a female it was shown that if such a male were moved 
rapidly and then stopped on the bottom it was treated by other males 
as a female. 
University of Michigan. 
AN ADULT DIEMYCTYLUS VIRIDESCENS WITH BIFURCATED 
TAIL, 
(With one plate.) 
BY BERTRAM G. SMITH. 
From a pond near Ann Arbor, Michigan, the writer captured an 
adult male Diemyctylus viridescens having the tail forked at the ex- 
tremity in a vertical plane, each ramus of the forked portion having a 
distinct vertebral column. The general appearance is shown by the 
accompanying photograph (Fig. 1). Perhaps it would be more ac- 
curate to say that the ventral portion branches off from the main axis 
of the tail. 
Sections show that the bifurcation is trulv vertical, and that each 
branch possesses well developed vertebrae and a spinal cord. The 
spinal cord of the ventral ramus is not continuous with that of the 
dorsal ramus, but is perhaps connected with it by nerve fibers. 
This is apparently not a case of “spina bifida” in the usual sense, 
for in spina bifida of the type familiar to embryologists the tail is 
divided in a horizontal plane. It seems more likely that the condition 
in this specimen is the result of injury with subsequent regeneration, 
as described in the experiments of Tornier. 1 
Tornier inflicted a double injury in the caudal region of a newt (Tri- 
ton). The more posterior of the two injuries was effected by cutting off 
the tip of the tail, either completely or so nearly that it afterwards 
dropped off. The more anterior of the two injuries was just sufficient 
to expose a vertebral process, either dorsal or ventral. The tip of the 
tail was regenerated, while a second caudal lobe grew from the more 
anterior injury. Tornier characterizes the production of the anterior 
lobe as a process of “super- regeneration,” induced by the more pos- 
terior injury. From his account it does not appear that an actual 
vertebral column developed in the regenerated region, but only a car- 
tilaginous or bony axis; possibly the former might have occurred had 
the experiment been given sufficient time. 
Zoological Laboratory, 
State Normal College, 
Ypsilanti, Michigan. 
Hornier, Gustav. Uber experimentell erzeugte dreischvanzige Eidechsen und Doppelgliedmassen 
von Molchen. Zoologischer Anzeiger, 20, 1897, pp. 356-362. 
