728 The American Naturalist. 
Each appendage possessed a functional anus. The left 
appendage appears as a continuation of the body, three 
somites serving to form a gradual transition from the thicker 
trunk to the thinner appendage. The right appendage springs 
out from the gaping suture between the trunk and the first of 
the three transitional left somites; where this origin of 
the right branch occurs there is a slight constriction not repre- 
sented at all upon the left branch. The method of bifurcation — 
seems thus similar to that figured by Robertson, fig. 4. E 
Very recently C. Dwight Marsh (8) records a two-tailed — 
earthworm found in Wisconsin. While alive both tails appear — 
of equal importance, but in alcohol one division is markedly — 
constricted where it joins the body and appears as a mere lat- 
eral branch. Each appendage has a branch of the intestine — 
and of the nerve trunk, as well as a functional anus. 
alcohol the specimen is only 34 mm. long, the tails each 
12 mm. ee 
Among the marine polychetous annelids instances of dupli- 
cation of the main axis have been recorded for several most 
widely separated families. 
Thus amongst the sedentary Serpulide, Edouard Claparéde | 
(10) found a Salmacina incrustans in which the posterior end 
was bifurcated as in fig. 2, each part having an anus. 3 
Among the nearly related family Sabellidæ, Brunette (11) 2 
found, in an unknown species of Branchiomma, one case in a 
which there were two posterior ends, the smaller one making 
an angle of 30° with the larger. The smaller end isa newly | a 
formed one having the fecal groove less marked than upon 
the older end, and the ventral shields scarcely visible. The 
whole annelid is small, 6 em. x 6 mm., while the new posterior 
end is 1 cm. long and attached about 15 mm. from the tip of the 
older posterior end. Here then we have to do with. a case of 
unequal bifurcation, one part appearing as a new formation 
grown out from the side of the normal animal near its poste- 
rior end. : 3 
Among the errant Polychete, in the family Syllide, Paul 
Langerhans (12) found a remarkable case of bifurcation, not 
of the posterior, but of theanterior end. This, the only well 
E 
