428 MR. R. C. LEWIS ON 
posterior border than in C. lagorchestis (figs. 16, 22). The fim- 
briation is in the form of a regular serration in the earlier 
proglottides (fig. 21), only overlapping half the succeeding pro- 
glottis, but in older proglottides these fimbriations are much 
elongated to form a mass of elongate hair-like projections which 
cover two or three of the succeeding proglottides. These pro- 
jections become more elongate towards the posterior end and 
project 4 or 5 mm. beyond the posterior segment (fig. 16). In 
no described Cittotenia is this sheath from the hind border of 
each proglottis broken up at its free edge in such a marked 
degree into hair-like lappets which project so far backwards over 
the succeeding proglottides. 
Considerable difficulty was experienced in working out the 
internal structure of this species, because several of the stvobile 
were mounted whole, and no trace of reproductive organs was 
observed in any of the proglottides (fig. 16). This was 
confirmed by series of sections throughout the strobila, which 
showed absence of reproductive organs (fig. 25). This was the 
more remarkable, in that the specimens without reproductive 
organs were not smaller in size, nor did they have fewer segments 
than those found with reproductive organs. 
In the forms found with reproductive organs no trace of these 
was to be seen in the first 50 segments, after which an abrupt 
transition was met with and proglottides were found with 
reproductive organs. The reproductive organs reach maturity 
very rapidly, and very few segments contain them in a rudimentary 
state. 
Again, after the 120th segment no reproductive organs were 
found. The segments with reproductive organs therefore 
were situated in the median portion of the strobila. This is in 
contrast with all other species of Cittotenia, where the first 
rudiments of the reproductive organs appear in the segments 
immediately behind the head. 
The musculature is similar to that described for C. variabilis 
Stiles. The sub-cuticular layer, consisting of longitudinal and 
transverse layers, is especially well developed. The excretory 
system appears also to agree with the condition found in 
C. variabilis, but no reservoir was detected on the posterior 
proglottis, and the ventral canals discharge by a simple pore on 
the last proglottis, as in C. lagorchestis. The ventral canal is 
especially large and occupies a large part of the lateral field. One 
main longitudinal nerve trunk is present on each side dorsal to the 
two excretory vessels, but the details of the nervous system could 
not be determined in these specimens killed and fixed in alcohol. 
Male Reproductive Organs. 
There is only one testis-sac on each side, which is large, 
‘4 mm. in diameter, and filled with a mass of developing sperm 
clusters (figs. 30 & 31). It is situated in the dorsal anterior 
field of each segment, a little nearer the median field than 
