310 KAMAKICHI KISHINOUYE : 



that of the Plecostei is obvious. The skeleton of the ScombridiB is unique 

 in many res^Dects, but it is more or less related to that of the Serranidfe, and 

 it has a remote relation to the Carangidii). The characters of the skeleton 

 of different scombroid fishes may well be understood by comparing the middle 

 traiLSveree sections of veiiebrse, shown in PI. XYI. 



In the Scombridse the skeleton is vfeak and brittle. The cranial bones 

 are thin, and not firmly connected together at the anterior part. The 

 vertebrae are notably small, and only a httle differentiated in form in different 

 regions of the Ijody (figs. 7, 30). They are rather loosely connected 

 and devoid of deep grooves. The neural and hcemal spines, interspinous 

 bones, and Suspensorium of the mandible are naiTow and slender. In the 

 Cybiidse tbe skeleton is also brittle. The ha3mal spine is scarcely develoi»d 

 in the preeaudal region (figs. 38-42). The neural spine of some anterior 

 precaudal vertebrae is broad. Except these broad neural spines, the remaining 

 neural and ha3mal spines, and interspinous bones are weak and slender. The 

 skeleton of Sarda (figs. 11, 42) and G/jmnosarda (figs. 12. 88) approaches 

 the skeleton of the Plecostei in the developmeüt of the lateral keel, in the 

 vertebra of the caudal peduncle, and tbe inseparable connection of these 

 vertebn^ with each other. Grooves and ridges in vertebra3 become conspicuous, 

 and the substance of the vertebrae becomes hard and compact, as the fish is 

 more highly si^eciahzed. 



In the Plecostei ths skeleton is luird, compact, and the cranial bones are 

 very firmly connected. The vertebrae are compai-atively large, have mnuj deep 

 grooves, and their diflereatiation in different regions is remarkable (figs. 13-15, 

 49-52, 57-60, 64). The neural and haemal s]Dine3 of the vertebral column 

 are thick and the interspinous bones are very broad. TLe development of long 

 haemal spines in the precaudal region is remarkal)le. The so-called inferior 

 foramen is very broad, especially in the Katsuwonidre, forming a basket-work 

 of the haemal process. In this family the opihsvmal spine or bonj' ^Jedicle of 

 Staeks is particulai-ly developed between the centrum of luiiny vertebrae and 

 their haemal arch. 



Skull. 

 In the scombroid fishes the skull is generally tiiangularly pjTamidal, and 



