EXPLANATION OF PLATE VII. 



Fig. 1. Caudal skeleton of Cottus gohio; h, actinophores or basilar interneural carti- 

 lages; ep, epural ; hy, hypural elements; «, urostyle. x 8. From Lotz. 



Fig. 2. Candal skeleton of Percafluviatilia; e/>, epural, ?ii/,hyparal elements; &, basilar 

 cartilages or actinophores; u, urostyle; in, intercalary cartilages, x 3. 

 From Lotz. 



Fig. 3. Gephyrocercal caudal extremity of Echiodon dentatus ; c, centra; ep, epural; 

 hy, hypural processes; i, interspinous cartilages; h, hiatus between dorsal 

 rays rd and post-anal rays rv. x 17. After Emery. 



Fig. 4. Caudal extremity of Fierasfer acus; ep, epural processes; c c c, centra not in 

 contact ; ch ch ch, membranous or cartilaginous intercentral intervals ; uch, 

 exserted end of chorda or urochord ; h, hiatus between last dorsal rays rd 

 and last post-anal rays rv. x 55. After Emery. 



118 1098 



