A NEW MAMMALIAN CESTODE. 1053 
to Fuhrmann’s genus Aporina, among the characters of which 
genus is the lack of these pores. Fuhrmann, however, has 
pointed out * that even if in the future examples of Aporina alba 
be met with in which the sexual ducts reach the exterior, the genus 
Aporina will not be invalidated thereby. I may use the same 
argument with regard to the species of Cestode which I describe 
in the present paper. But if I were compelled to ignore the 
rudimentary vagina, the genus would have to be placed in the 
subtamily ‘Anoplocephaling of the family <Anoplocephalide, 
though it would remain distinct. 
Comparison with Shipleya inermis Fuhrmann. 
Although at first sight, and indeed after some study, I was 
disposed to place the present species in the same genus as 
Shipleya, and even to consider the possibility of the iwe forms 
being identical, Iam no longer able, after a more profound study of 
this species, to identify even generically the two forms referred to. 
It is remarkable, however, that in pursuing my supposed new 
species through the dichotomous table of Mr. Ransom I arrived 
at the genus Shipleya, the only difference apparently being the 
Jack of spines upon the cirrus in my species. A reference to 
Fuhrmann’s original description of Shipleya inermis shows, bow- 
ever, that there are other differences, and of importance. Shipleya, 
like other Acoleide, has a body-wall which is traversed by a 
complicated series of muscles. Outside of the inner transverse 
muscles is a double row of large bundles; outside of this again 
are four separate and very thin layers of transverse fibres, 
between each of which is a layer of longitudinal fibres. Such a 
section is figured by Fuhrmann. In my species, on the other 
hand, there is but a single and the usual layer of transverse 
fibres, outside of which is a layer of singly disposed longitudinal 
fibres, an arrangement in marked contrast to that of Shiples ya. 
In the second place, although my species from Hrethizon has 
a large cirrus-sac, this organ is not so large as in Shipleya, 
where it measures no less than one millimetre in length and 
is, furthermore, covered by diagonal fibres. In my species 
the fibres have the arrangement described above on p. 1045. 
There is, however, in both species the accurate alternation in 
the position of the genital apertures. But we shall see directly 
that another tapeworm, more probably allied to my species, 
shows the same regular alternation of these pores from right to 
left side of the body. I do not think it likely that I have failed 
to see the spines upon the cirrus if they were really present and 
like those of Shipleya; for Fuhrmann described these spines as 
arranged in three rows and very like the thorny spines of the 
Acanthocephala. I have seen nothing of the kind, though the 
cuticle covering the organ is composed of almost separate rod- 
like spinules. These, however, are closely set and in contact, 
* Zool. Jahrb., Suppl.-Bd. x. 1908, p. 39. 
