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 paim of spines to 
this embryo; if there are any, they must be very small. 
A number of points were added to W einland's description, and sev 
eral errors corrected by Leuckart (1863. pp. 397-400) from a study of 
material obtained from AVeinland. 
That Ilymenolepis jlavopiuictata AVeinland from man is in reality 
the same form as Tsenia leptocephala Creplin and Tcenia diminuta 
Rudolphi was definitely established by Grassi (1S881). 
The most complete anatomical description of Ilymenolepis dirninuta 
which has appeared is that given by Zschokke (1889. pp. 63-73. figs. 
:>l-24). 
Two species very similar to II. dirninuta are known. Hyrnenoleyris 
relicta (Zschokke) from the rat. and II rnegaloon Linstow from 
a gopher {Sperrnophilm sp.). The former, although described by 
Zschokke as a distinct species, is so nearly like II. diminuta that it 
is a question whether the two ought not to be united in the one spe- 
cies, II. dirninuta. Practically the only distinguishino* characteristics 
seem to be difi'erences in the length and the number of segments, upon 
the basis of which it would be a very difficult matter to draw a line 
separating the two forms. The second form. II. rnegaloon, which 
was described briefly by Linstow (1901). resembles II. dirninuta 
except in one or two minor details, and is a yery nearly related 
species. 
ANATOMICAL DESCRIPTION. 
The following account of the anatomy of Hyrnenolepis dirninuta is 
based upon preyious descriptions supplemented by original obserya- 
tions upon specimens both from man and from rats: 
EXTERNAL ANATOMY. 
Strohila. — The length yaries from 10 to 60 cm. and the breadth pos- 
teriorly is from 2.5 to 4 mm. or as much as ( i) 7 mm. (Packard. 1900). 
Head. — The size and form of the head (figs. 71-74) are yariable. 
200 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. 
Bostellurn. — The rostellum is in all essentials exactly similar to the 
rostellum of Ilymenolepis carioca (see Ransom. 1902). When in a state 
of retraction the rostellum ffigs. 72-74) has the appearance of a small 
elongated muscular sac embedded in the substance of the anterior part 
