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TRI-RADIATE TAENIA CRASSICOLLIS RUD. 
By S. 0. YOSHIDA. 
{Zoological Institute, Science College, Imperial University, 
Tokyo, Japan.) 
(With Plate XX.) 
Among other cestodes collected by me some years ago were specimens 
of the prismatic malformation of a tape-worm which I have recently 
examined. This abnormality in the taenioid group of cestodes has been 
frequently reported in Europe, especially in Taenia saginata, since 
Andry’s case was first described in 1700. This malformation is known 
as Taenia‘tv\dre,’ ‘ triquestre,’ or ‘prismatique’ in French ; as ‘dreikantige’ 
in German, and as ‘ tri-radiate ’ or ‘ prismatic ’ in English. But as far 
as my knowledge goes, we do not find a full description of any such 
abnormality in Taenia crassicollis, though a brief description of it was 
given by Bremser in 1819 and 1824. It is now recorded for the first 
time from Japan. 
The material upon which the following description depends was sent 
by the teacher of a certain secondary school in the Province Shinano, 
the middle part of Japan, who collected it from the intestine of a house- 
cat. The total length of the specimen is 220 mm., and its segments are 
about 240 or more in number. The length of the segments gradually 
increases posteriorly, reaching a maximum of 7 mm. at the last segment, 
while the first segment only measures OT mm. in length. The width (of 
each wing of the prismatic worm) of the first segments is also small, 
abont 0’6 mm., but rapidly increases posteriorly and attains its maximum 
width of 2 5 mm. at a distance of one-fourth of the total body length 
from the head. This width continues nearly throughout the middle 
third of the body, and then it gradually diminishes toward the posterior 
extremity where the width is 1'5 mm. 
