336 
KAMAEICHI KISniNOUYE : 
Vertebral Column. 
The general feature of the vertebral column of the different types of the 
scombroid fishes may easily be understood by examining Plate XIV, showing 
the middle transverse section of vertebrae. 
In the Scombridae (fig. 30) the number- of vertebrae is not large, being 
31 in total, and the number of the precaudal vertebrae is nearly the same as 
that of the caudal. The vertebrae are small, longer than broad, nearly equal 
in size and form, and are articulated with each other rather loosely by means 
of short, small zygapophyses. In Scomber japonicus, however, the anterior 
zygapophyses, both superior and inferior, are very broad in the caudal vertebrae, 
and their anterior margin is divided. The articulating surfaces of the first 
vertebra with the skull are two, separate, and turned axially, just opposite to 
the ordinary case. Thus a pair of stout processes at the dorsal corner of the first 
vertebra grasps the posterior end of the basioccipital (fig. 30, C). The neural 
spine is nearly equally slender, throughout the whole length of the vertebral 
column, and the first spine is never free. The anterior concavity of the 
vertebra is a little shallower than the posterior. The neural and haemal spines 
are nearly straight, oblique, and generally they are compressed anteroposteriorly. 
The parapophyses are not developed, and the haemal spine is scarcely developed 
in the precaudal region. Almost all the precaudal vertebrae have their neural 
canal divided into two. The lower canal is for the spinal cord, it is entirely 
covered by a bony roof, separated from the upper canal for the dorsal ligament. 
The lateral transverse ridge in the anterior precaudal vertebrae is quite peculiar 
to this family (fig. 7). The last vertebra is not fused with the hypural bones. 
In the Cybiidae the total number of vertebrae is very variable, generally 
over forty. The least number of them in my collection is thirty one in the 
genus Grammatorcynus , and the maximum number sixty four in Acanthocybium 
solandri. The relative number of the precaudal and caudal vertebrae also 
varies. Generally the precaudal vertebrae are less in number than the caudal. 
In Acanthocybium solandri and Sarda orientcdis, however, the precaudal vertebrae 
are more numerous, while in Sarda chilensis and Gymnosards nuda the number 
of vertebrae in both regions is exactly the same. Vertebrae are generally very 
short, disk-like near both extremities of the body (fig. 41). In most vertebrae 
