F. W. Flattely 
271 
Among much that is doubtful in regard to the life-history of species of 
Moniezia one fact seems quite clear and provides a valuable hint from which 
the investigation of the problem may perhaps most profitably be tackled. It 
is the tender age at which adult, fully grown worms are found in the lamb’s 
intestine. In America, according to Curtice (1890), individuals of Taenia 
(Moniezia) expansa are found measuring 2-5 yards long in lambs from 2-4 
months old. This is one of the first points to which I directed my attention 
and I found that on a farm close to Aberystwyth proglottids began, in 1914, 
to appear in the faeces of lambs on April 10th, approximately six weeks after 
the lambs had been dropped. (I have since observed proglottids in the faeces 
of a lamb not less than four, and not more than six, weeks old.) On April 28th 
I observed a string of proglottids some 12 inches long in the faeces of a lamb. 
These showed the ovaries and yolk glands fully developed, but the uterus had 
not begun to spread. It is evident that for the worm to attain this condition 
in so short a period infection must take place either at, or very shortly after, 
birth. If we accept provisionally the idea of an intermediate host, then it is 
evident that the creature—slug, earth-worm, beetle, tick, louse, mite or what 
not—must be present on the pasture at lambing time, and, moreover, must be 
present in considerable numbers, for it is not ah isolated lamb that is infected 
but practically all the lambs of a flock. Further, most lambs harbour not one 
worm but a number. In Britain, however, the variety of invertebrate life to 
be observed upon a pasture at lambing time, is, generally speaking, so small 
that if an intermediate host really does occur, the task of finding it should 
not be one of extraordinary difficulty. 
A first visit to the above-mentioned farm near Aberystwyth was employed 
in examining, as an obvious preliminary step, the udders and wool of a number 
of ewes for parasites, but none was present. The udder region was scraped with 
a knife and the resulting epidermal scales, dirt, etc., were removed to the 
laboratory for microscopical examination. The object of this was to establish 
the possibility of tapeworm eggs or larval forms being transferred from the 
pasture to the belly of the ewe, and thence being ingested by the lamb when 
sucking. For, assuming that infection should occur directly from the egg, 
the lamb would hardly pick up the latter immediately from the pasture since 
in the first few weeks of its life it does little more than nose the grass in a very 
superficial manner. 
The result of this microscopical examination was also negative. Next, 
grass was collected from the pasture at random, washed thoroughly, and the 
washings examined for possible larval forms. The result was negative. The same 
water was allowed to stand and was re-examined from time to time, but still 
without result. 
On March 12th a number of specimens of the slugs Agriolimax agrestis and 
Arion hortensis were collected from the pasture and dissected on the chance 
of their furnishing an intermediate stage, particular attention being paid to 
the pulmonary cavity, the wall of which was cleared and examined micro- 
18—2 
