SEA-FISHERIES LABORATORY. 99 



worm is E. minimum ; but the presence of a neck, and the 

 absence of long cirral spines indicate that it is E. gracile. 



Neither van Beneden nor Zschokke apparently 

 attached much importance to the absence of a myzo- 

 rhynchus. Yet the presence of this most characteristic 

 organ is part of the definition of the genus Echeneibothrium. 

 I follow Linton in his suggestion, that the absence of this 

 structure justifies the removal of a cestode possessing 

 Echeneiform bothridia from the genus Echeneibothrium. 

 Now there is no figure of E. minimum which shows a 

 myzorhynchus, and the organ is absent in E. gracile also. 

 I examined the specimens here described very carefully 

 and could see no part anterior to the pedicels ; and there 

 is no evidence of a proboscidial structure in a series of 

 sections made from one of the worms. It is true that a 

 small, knob-like protuberance could be detected, but I 

 think that this was only a hump on one of the pedicels. 

 The myzorhynchus in the specimen of E. variabile figured 

 on page 85, and the rosette-like structure mentioned by 

 Olsson are very striking and prominent features of the 

 anatomy of these animals ; and even in the specimen of 

 E. dubium figured on page 94, the myzorhynchus is very 

 obvious. It seems therefore that we are justified in placing 

 both E. minimum and E. gracile in a distinct genus, as is 

 suggested by Linton. Whether or not these two forms are 

 specifically distinct is a more difficult question. 



