Oct. io, 1913 
Cysticercus Ovis 
35 
than half the total length of the hook; and as the genital sinus and genital 
papilla are very small, the two species may be readily distinguished from 
each other. 
Of the less common or less known tapeworms of the dog the species of 
Dibothriocephalus and Mesocestoides are immediately to be distinguished 
from Taenia ovis by the absence of cephalic hooks and rostellum and by 
the location of the genital pores in the ventral median line of the segment. 
Likewise, the absence of hooks and rostellum distinguishes Ophidioiaenia 
punica (Proteocephalus punicus) 1 from T . ovis. 
The remaining species of tapeworms known to occur in the dog are 
Taenia balaniceps , T. brauni, T. brachysoma , and T. krabbei , all of which, 
with the exception of the last, may be readily distinguished from T. ovis 
upon the basis of their published descriptions. 
Taenia balaniceps Hall (1910, pp. 139-151, figs. i-8) differs from T. ovis 
in various particulars, among which may be mentioned the following: 
The worm is smaller, the length of the longest specimen being only 24 cm.; 
the head is smaller, not exceeding 75 2/4 in breadth, and the segments in 
corresponding stages of development are smaller. The hooks are smaller, 
93 to 9 8/4 being given as the limits of length of the small hooks and 145/* 
as the length of the large hooks (fig. 2.) The testicles extend practically 
to the posterior border of the segment, as in T. hydatigena . The lateral 
branches of the uterus, instead of being slender and more or less separated 
by intervening spaces as in T. ovis , are comparatively thick and are 
pressed close together. 
Taenia brauni Setti, 1897 (Setti, 1897b, pp. 210-214, pi. 8, figs. 9-14), 
differs from T. ovis in that it is much smaller, its total length being from 
15 to 18 cm., and the size of the posterior segments 5 or 6 mm. long by 3.5 
mm. wide. T. brauni was described as lacking a true rostellum but as 
possessing a double crown of 30 hooks, the large hooks measuring 130 to 
140/£, though in some cases only 95 to 100/4 in length, and the small hooks 
usually 85 to 90/4, occasionally 70 to 75/1, in length. T. ovis, however, has 
a well-developed rostellum and hooks considerably larger than the dimen¬ 
sions given for T. brauni and is thus clearly a different species from 
the latter, though the two forms agree in possessing prominent genital 
papillae and perhaps are similar in regard to the branches of the uterus, 
as Setti states that the lateral branches are numerous, slender, and per¬ 
pendicular to the medium stem. 
Taenia brachysoma Setti, 1899 (Setti, 1899c, pp. 11-20, pi. 1, figs. 1-9), 
is also a much smaller species than T. ovis , specimens with gravid seg¬ 
ments being not over 10 cm. long and not over 3 mm. in maximum 
width. The number of hooks is 30 to 32. The large hooks measure 135 
to 145/4 and the small hooks 95 to 105/4 in length, the former thus being 
considerably smaller than in T. ovis, and the latter averaging smaller. 
The ventral roots of the small hooks are described as having a median 
groove, thus presenting a condition intermediate between simple and 
1 This species, as pointed out by Hall (1910, p. 146), is probably not a true parasite of the dog. 
