84 TRANSACTIONS LIVEEPOOL BIOLOGICAL SOCIETY. 



Echeneibothrium, van Beneden. 



A large number of specimens of cestodes belonging 

 to this genus were obtained from various species of Kay 

 during the present year, and it seems useful, in view of 

 the great variability of character exhibited by the various 

 species belonging to this group, to describe these worms 

 in some detail. The genus Echeneibothrium is defined by 

 the presence of four Echeneiform bothria carried on con- 

 tractile pedicels; by the absence of any armature of the 

 bothria; and by the presence of a contractile my/o- 

 rhynchus, at the apex of which there is a terminal os. 



(3) Echeneibothrium variabile, van Beneden.* 



This is the typical species. The bothria, pedicels, and 

 myrzorhynchus are highly contractile, and very different 

 appearances are presented by the worms when they die, 

 and also according to the mode of preservation employed. 

 I describe here two forms which appear very frequently in 

 Irish Sea fishes. 



I. Pear-shaped niyzorhynchus, with terminal os 

 leading to a concealed proboscis. Bothria typical in form 

 and structure. Fig. 4, page 85, represents the appearance 

 of the scolex of a specimen killed in fresh water and 

 preserved in formalin. The worm was unstained and Mas 

 examined in water. The measurements are : 



Greatest diameter of 'the scolex : 1*2 I mm. 

 Diameter of myzorhynchus : 058 mm. 

 Diameter of terminal os: 0*2 mm. 

 The bothria present the typical structure: they are 

 leaf-shaped with eight or more transverse, and one longi- 

 tudinal costae. Their apices are curled over, and in the 

 bothrium at the lower right-hand corner of the figure, one 

 of the lateral margins is also curled over. The scoles is 

 # " Vers cestoides," p. 113, PI. III. 



