





Bathyphylax, as in the hollardiins, is about 40 to 65% 

 SL, while in Atrophacanthus and Tydemania it is about 

 30 to 35% SL, and in Macrorhamphosodes and Halimo- 

 chirurgus about 15 to 25% SL. The eye of Johnsonina is 

 larger than in any other triacanthodid at comparable 

 size, and it is the only genus to feature a large ocellated 

 eye spot on the body, just below the soft dorsal fin. 



In Triacanthodes, Mephisto, Johnsonina, and Para- 

 triacanthodes herrei, as in hollardiins, the basal flange of 

 the pelvic spine and the region of the pelvis against 

 which it slides are smooth, allowing for only a single posi- 

 tion of locking the erected spine against the pelvis, while 

 in P. retrospinis, Atrophacanthus, Bathyphylax, Tyde- 

 mania, Macrorhamphosodes, and Halimochirurgus these 

 two regions are grooved, allowing for multiple positions 

 of locking the erected spine against the pelvis. 



