84 
face of the egg a wrinkled appearance, though the first shell is in reality entirely 
smooth. The large cavity which is formed by these two outside shells contains a 
fluid (this fluid, which has the appearance of albumen, turns milk white when 
brought into contact with water. Such an albuminous fluid between the two egg- 
shells has also been noticed by Dujardin in the eggs of a Taenioid from Fringilla 
domestica, L.), in which swims the small globular embryo (measuring only 0.024 
mm.), inclosed in a third shell, closely attached to it, but of considerable thickness 
(0.001 mm.). IVe can not state with certainty that there are three pail's of spines to 
this embryo; if there are any, they must be very small. 
A number of points were added to Weinland's description, and sev- 
eral errors corrected by Leuckart (1863. pp. 397-400) from a study of 
material obtained from Weinland. 
That Ilymenoleph fiavopunctata AVeinland from man is in reality 
the same form as Tsenia leptoceplicda Creplin and Tsenia dirninuta 
Rudolphi was definitely established by Grassi (18881). 
The most complete anatomical description of Tlymenolepis dtmimda 
which has appeared is that given by Zschokke (1889. pp. 63-73. figs. 
21-24). 
Two species veiw similar to II. dirninuta are known, Ilyrnenolepis 
relicta (Zschokke) from the rat. and II rnegaloon Linstow from 
a gopher {Sperrnophilus sp.). The former, although described bt’ 
Zschokke as a distinct species, is so nearly like II. dirnimda 
is a question whether the two ought not to be united in the one spe- 
cies, II. dimimda. Practicallv the onlv distinguishing characteristics 
seem to be difi'erences in the length and the number of segments, upon 
the basis of which it would be a veiy difiicult matter to draw a line 
separating the two forms. The second form, II. rnegaloon^ which 
was described briefly lyv Linstow (1901). resembles II. dirninuta 
except in one or two minor details, and is a A’ery nearly related 
species. 
ANATOMICAL DESCRIPTION. 
The following account of the anatomy of Ilyrnenolepis dirninuta is 
based upon previous descriptions supplemented by original observa- 
tions upon specimens both from man and from rats: 
EXTERNAL ANATOMY. 
Strohila. — The length varies from 10 to 60 cm. and the breadth pos- 
teriorly is from 2.5 to 4 mm. or as much as (?) 7 mm. (Packard, 1900). 
Head. — The size and form of the head (figs. 71-74) are variable, 
2u0 to 600 p in width, almost globular, but rather flattened; with 
4 suckers, placed somewhat anteriorly, 80 to 160 p in diameter, and 
a rudimentary, unarmed rostellum. 
Rostellurn. — The rostellum is in all essentials exactly similar to the 
rostellum of Ilyrnenolepis carioca, (see Ransom, 1902). AVhen in a state 
of retraction the rostellum (figs. 72-74) has the appearance of a small 
elongated muscular sac embedded in the substance of the anterior part 
