Characteristics

1. Arms
   1. Hectocotylus with 22-26 suckers.
      
   
   

   Sthenoteuthis pteropus. © Elsevier
2. Tentacles
   1. 
      
   
   
   
   

   Figure. Oral views of the left and right tentacle bases of S. pteropus showing the relationship between the carpal knobs (colored yellow) and the number of more proximal suckers. Note that the proximal carpal locking-sucker is absent from the tentacle on the right. Drawing modified from Pfeffer (1912).
3. Funnel/mantle locking-apparatus
   1. Funnel and mantle components not fused.
      
   

   Figure. Frontal views of the funnel (left) and mantle (right) components of the funnel/mantle locking-apparatus of S. pteropus showing xxxxxx.

   2. Photophores
      1. 
         
         
         

         Figure. Ventral view of the subcutaneous photophores of S. pteropus. Diagramatic illustration from Roper (1963).