F. W. Flattely 
275 
this batch. In some the ‘'neck'’ is extremely long and thin, and it is only 
beyond a distance of several inches that the proglottids begin widening out. 
In others the neck is very short and the proglottids rapidly become very 
broad. 
June 12th. In the string of a single lamb from the slaughter-house on this 
date, I found 75 individuals , the aggregate length of which was 150 feet. The 
worms showed the same differences in appearance as those in the preceding 
batch. There is no doubt about the extraordinary degree of infection in this 
case, as 75 was the number of scolices found. Curtice states that the number 
of individuals occurring in the same intestine may be from two or three to a 
hundred, but that it is unusual to find more than half a dozen adults 
together. He himself observed as many as 14 adult worms in a lamb four 
months old. 
According to observations made at the time, the above worms belonged 
to one or other of two species, viz. M . expansa and M . trigonophora, the former 
being much the more numerous. If my identification of the latter species is 
correct then the two species occurred together in the same lamb. The identifi¬ 
cation was based on microscopic characters and not on externals which, as 
Stiles has pointed out, vary tremendously according to the age of the worm 
and the state of contraction. Thus, M. expansa may show precisely the 
differences which have been above noted, viz. in some individuals the neck 
may be extremely long and thin, the proglottids widening out very gradually, 
while in others the neck is very short and the proglottids become quite broad 
only a short distance behind the scolex. The characters which led me to 
identify some of the individuals as M. trigonophora were mainly (1) the 
presence of interproglottidal glands grouped around blind sacs, and (2) the 
arrangement of the testicles in two triangles, one at each side of the segment. 
I am anxious, however, not to attach too much importance to the occurrence 
of M. trigonophora in Wales, since I have not since found it elsewhere, and since 
also the triangular arrangement of the testicles is not absolutely decisive, 
M. expansa itself occasionally showing the same arrangement in certain seg¬ 
ments. 
In addition to the specimens above noted which were obtained by myself 
from the Aberystwyth abattoirs, I was later able to examine a large batch 
procured for me from the same source through the kindness of Mr T. A. 
Stephenson, M.Sc. These proved without exception to be specimens of M. ex¬ 
pansa. A few notes on these are appended. In Nov. 1919, I further received 
from Mr C. L. Walton, M.Sc., a strobila from a lamb in all probability 
reared in Carnarvonshire and grazed in Anglesea. From the shape of the 
proglottids (longer and narrower than those of M. expansa ), position of the 
genital pores, absence of interproglottidal glands and, finally, the character 
of the scolex, I have no hesitation in putting this specimen down as M. alba. 
