EXPLANATION OF PLATE VI. 



FlQ. 1. Caudal skeleton of Salmo fario; h and V, basilar cartilages or actinophores ; ep, 

 epural ; /ly, hypural elements ; m, lateral membrane bone, which has had 

 an epnral cartilaginous element as its nucleus ; in, intercalary cartilage ; u, 

 urostyle ; op, opisthural element. X 3. After Lotz. 



Fig. 2. Caudal skeleton of Salmo salar; ep, epural elements ; ep', laterally displaced epu- 

 ral elements, from which the membrane bone m has extended in perichon- 

 drium ; b and b', basilar cartilages or actinophores ; in, intercalary cartilages ; 

 hy, hypural boues ; u, urostyle ; op, opisthural rudiment, nat. size. After 

 Lotz. 



Fio. 3. Caudal skeleton of BarbusflurnatiliB ; ep, epural^ and ep', laterally displaced epu- 

 ral bones ; hy, hypural bones ; in, intercalary cartilages ; b and b', basilar 

 cartilages or actinophores; p, lateral tuberosity for the attachment of the 

 caudal muscles ; u, urostyle ; op, hypaxial opisthural rudiment. X 2. 

 After Lotz. 

 116 1096 



