340 
KAMAKICHI KTSHINOUYE : 
developed, and is found in tlie precaudal region as well in Katsuwonus and Euthyn - 
nus (figs. 57, 58) ; but in Auxis the foramen is found poorly developed and in 
a few posterior caudal vertebrae only. In this family a pair of special 
protuberances appear in a few anterior vertebrae. These protuberances lie just 
behind the superior zygapophyses, and they serve to furnish points of attach¬ 
ment to a pair of strong tendons of the lateral muscle. 
In the Plecostei the neural and haemal spines and other processes from 
vertebrae for the mutual articulation are well developed. The neural spine of 
certain anterior vertebrae is broad and rough for the insertion of muscles, 
and in bonitos the neural arch of these vertebrae is perforated with numerous 
pores of different sizes. The other neural spines are long, slender, laterally 
compressed, and nearly vertical to the vertebral column at then* origin. 
The haemal spine is remarkably well developed in the precaudal region 
in tunnies ; but in bonitos the spine is scarcely developed in this region. 
However a median spine of quite new origin makes its appearance in the 
Katsuwonidae. It was first described by Starks (69) under the name of 
pedicle ; but I propose to name it the epihaemal process. The spine is 
developed between the centrum and the haemal process or the haemal arch, 
and is best developed in the posterior part of the precaudal region. The anterior 
superior zygapophyses of anterior precaudal vertebrae are long, more or less 
bent inward at the lower margin in the Thunnidae ; but they are more or less 
triangular pyramidal in the Katsuwonidae, and there is an accessory zyga- 
pophyses as in the Scombridae. The anterosuperior zygapophyses in the 
posterior portion of the vertebral column are elongated and flat, both in the 
Thunnidae and Katsuwonidae ; bnt in the latter family the accessory zyga¬ 
pophyses are formed beneath the ordinary zygapophyses to clasp the posterior 
superior zygapophyses between these two zygapophyses. In the Thunnidae the 
inferior zygapophyses are short and pointed at the end, more or less diverging 
from the middle of a vertebra, and they do not come into close contact 
with those of the nest vertebra, as in the Cybiidae. In the Katsuwonidae, 
however, the inferior zygapophyses of a vertebra are long and in close contact 
with those of the nest vertebrae. 
