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KAMAKIOHI KISHINOUYE : 
that of the Plecostei is obvious. The skeleton of the Scombridæ is unique 
in many respects, but it is more or less related to that of the Serranidæ, and 
it has a remote relation to the Carangidae. The characters of the skeleton 
of different scombroid fishes may well be understood by comparing the middle 
transverse sections of vertebrae, shown in PL XVI. 
In the Scombridæ the skeleton is weak and brittle. The cranial bones 
are thin, and not firmly connected together at the anterior part. The 
vertebrae are notably small, and only a little differentiated in form in different 
regions of the body (figs. 7, 30). They are rather loosely connected 
and devoid of deep grooves. The neural and haemal spines, interspinous 
bones, and Suspensorium of the mandible are narrow and slender. In the 
Cybiidæ the skeleton is also brittle. The haemal spine is scarcely developed 
in the precaudal region (figs. 38-42). The neural spine of some anterior 
precaudal vertebrae is broad. Except these broad neural spines, the remaining 
neural and haemal spines, and interspinous bones are weak and slender. The 
skeleton of Sarda (figs. 11, 42) and Gymnosarda (figs. 12. 38) approaches 
the skeleton of the Plecostei in the development of the lateral keel, in the 
vertebrae of the caudal peduncle, and the inseparable connection of these 
vertebrae with each other. Grooves and ridges in vertebrae become conspicuous, 
and the substance of the vertebrae becomes hard and compact, as the fish is 
more highly specialized. 
In the Plecostei the skeleton is hard, compact, and the cranial bones are 
very firmly connected. The vertebrae are comparatively large, have many deep 
grooves, and their differentiation in different regions is remarkable (figs. 13 -15, 
49-52, 57-60, 64). The neural and haemal spines of the vertebral column 
are thick and the interspinous bones are very broad. The development of long 
haemal spines in the precaudal region is remarkable. The so-called inferior 
foramen is very broad, especially in the Katsuwonidæ, forming a basket-work 
of the haemal process. In this family the epihæmal spine or bony pedicle of 
Starks is particularly developed between the centrum of many vertebrae and 
their haemal arch. 
Skull. 
In the scombroid fishes the skull is generally triangularly pyramidal, and 
