364 
TETRARHYNCIIUS ERINACEUS VAN BENEDEN. 
I. STRUCTURE OF LARVA AND ADULT WORM. 
By JAMES JOHNSTONE, B.Sc. 
{Fisheries Laboratory, University of Liverpool.) 
With Plates XIX—XXIV and 9 Text-figures. 
CONTENTS. 
' PAGE 
I. Introduction.364 
II. 
Distribution and life-history . 
365 
III. 
The Pleroeercoid larva . 
369 j 
IV. 
The scolex. 
374 
Bothridia . . ’ . 
375 ! 
Proboscides .... 
376 1 
Musculature of the scolex 
378 i 
Musculature of the proboscides 
380 
Excretory canals 
384 
Central nervous system 
385 
V. 
The integument .... 
392 
VI. 
The immature proglottis 
395 
Male genital organs . 
395 f 
Female genital organs 
402 
Musculature of the proglottis . 
409 : 
Excretory canals 
410 !' 
VII. 
The mature proglottis 
410 i 
References ..... 
413 
I. Introduction. 
My attention was first directed to this Cestode in 1906 when I was 
asked to examine several specimens of edible fish which had been 
exposed for sale in the public markets and had beeu condemned as 
human food on account of the presence of obvious, intrusive bodies in 
