COMrAlUTIVK STIUY OF SCOMBUOID FtSBES. 337 



six longihuliual grooves arc found; — dorsul mediau, vcutnil median, and two 

 IMvirs of lateral gi-ooves (figs. 8-12). Tlie vertebral oolumu of AcanthoojUwii 

 ^dandri (figs. 10, 39) aud Gijhhim Icoreanum is dlflercut from that of the f)tlior 

 foiTus iu liaving tbi-ee lateral gixjoves instead of two. Tlie first neural spine is 

 not always fused to the ceutnmi, nor forms a comjilete ring at the prosiniul 

 part, for the spinal cord. In the genus Sarda, however, the detachable neiu-al 

 spine of the firet vertebra foiius a complete ring, l)eing fused at the lower end. 

 Some anterior nem-al spines are broad and sti'ong. Tlie other neural aud liaemal 

 spines are sleudei" and weak, and in the middle of the body the}' imite to the 

 centrum of vei-teln-ae almost peiioeudicularly at least at their insertion (figs. 39, 

 41, 42), except in Cyhium chinense (fig. 40). They are not compressed laterally. 

 The last vertebra is coalesced with the hj^jm-al lx)nes aud forms a lozenge 

 shaped Ixjue, with a small mcchau notch at the ^Kisterior margin. Transverse 

 in'ixÄSses are not developed, but haemal processes and haemal spines of some 

 length ai-e foimd in many precaudal veiiebrae (fig. 38-42). Some of these 

 spines axa tmiied autei'iorly iu Cyhium ni2)lionium aud Gymnosarda nuda. The 

 hypiu^il process of the last haemal spine is notably prominent, aud the 

 vertebrae iu the caiKhxl ^»dimclo are remarkably small, gi'atlnally nanuwing 

 backwaixls, except iu the genera Sarda aud Gymnosarda. In these genera 

 the hypural process of the last haemal spine is uaiTow and the veiiebrae of 

 the caudiil i>3duucle are not modified iu size, but iu fonu, l)ecoming quadi-ate 

 prismatic, with their nem'al and haemal spines broad aud flat, as we find iu 

 the Plecostei. These spmes project backward nearly horizontally, aud firmly lay 

 hold of the succeeding vertebra. Iu these vertebrae the lateral ridges are 

 remarkal)ly developed to the lateral keels (figs. 11, 12). Iu these cases the 

 two vertebrae preceding the last vei-tebra are small and flattened anteroposte- 

 riorly and are capable of lateral movement. The inferior forameu is develo^jed 

 in some caudal vertebrae ; but generally it is small aud iucouspicuoas, os^xcially iu 

 the genus Cylnv.m. In the su^x^i-ior zyga|X)physes both the anterior aud jxisterior 

 pairs are Uu'ge. Iu the Scombridae aud Cybiidae the haemal canal of preciiudal 

 vertebrae is suddenly reduced in calibre in some anterior vertebrae. This is 

 due to the exclusion of the cardinal vein from the haemal caruil. 



In the Plecostei the total number of vertebrae is thirty rane, except in the 

 genus Kaisutvonns, which has fortj-one vertebrae. The vertebrae are articulated 



