219 
two portions, making the sphincter look almost double, in the other 
place there was no main lamella and the sphincter is with a broad 
base attached to the column. In the Campbell specimens the main- 
24 
lamella was mostly thin, as also in some of the Auckland spec¬ 
imens. There were more or less anastomoses between the muscle 
folds. In the sphincter I have often observed a parasite, as far I 
can see a Trematod (textfig. 24), once I have found it in the pen- 
non of a mesentery. It is possible that this parasite has had some 
