Plate 6. 



Tampsia chocoyensis Stephenson. View of the siphonal channels of the right- 

 hand individual shown in plate 5, about three-quarters natural size. (E), 

 anterior siphonal channel, and the slit or sinus a at the bottom of the chan- 

 nel. (S), the broad posterior siphonal channel and the narrow, deep, subor- 

 dinate channel alone: its center, Page 8. 



19 



