IM:il,- IV. 



(For letters see List p. MH |98|.) 



Fig. 1 : Siphonostomn lijphle. 



Fig. 1: Last two abdominal and anterior caudal vertebrae with doisal and anal fins, i'loni left side; 

 showing interspinous bones arranged in fanshaped groups, t: transverse process: v: wing- 

 shaped secondary process for attachment of fin-muscles; sp: inferior spine; a: anus; between 

 the latter and tlie abdominal vertebræ part of viscera is seen. 



Fig. 2 : Hippocampus breuirostris. 

 Fig. 2: Corresponding part to that of Fig. 1, from left side. 



Figs. 3 — 4: Siphonostoma typhle. 



Fig. 8: Anterior three vertebræ, from below (much enlarged); a; articular process, connecting with 

 skull; t: transverse process. 



— 4; The same, from left side. 



Fig. 5 : Syngnathus acus. 



Fig. .') : Anterior three vertebræ, from left side, n: nucliale in situ ipart of the laterally' e.vpandcd plate 

 cut away). 



Figs. 6 — 11: Siphonostoma typhle. 



Fig. () : Last abdominal vertebra, from right side, i, i : incisions in spinous process, for insertion of 

 interspinous bones. Other letters as in Fig. 1. 



— 7: The same from above. 



— 8; First caudal vertelira, from left side, i: interspinous bone; u: its terminal upper end; e; bony 



expansion just below the latter. 



— 9: The same, seen from behind, ia : inferior (open) arch. Other letters as in Fig. 8. 



— 10: Last caudal vertebra, left side, h^ h„: upper and lower hypural bones. 



— 11: Coalesced interspinous bones for anal fin with cartilages removed (much enlarged), e: bonj' 



expansions for connection with dermal scutes, originating just over terminal end u. 



Fig. 12: Nerophis œqiioreus. 



Fig. I'i: Three groups of interspinous bones for dorsal fin, fnim above; showing lateral bonj" expansions 

 (e) on the left side, and on the right side the same overlapped by the superior lateral (si) 

 and upper intermedial scutes (ii. The posterior 3 interspinous bones belong to one vertebra; 

 the 2 other groups each of 4 interspinous bones are supported eacli ))y one vertebra, the 

 smaller interncurals connected with the intermedial scutes i Ijeing the hindmost of each 

 group, u: terminal end of interspinous bones. 



