CARANGIDAE 47 



* 



process at each side of the neural canal extends upward and forward, 

 while just below it and separated from it by a notch is a small spine 

 or spur directed forward. On the posterior end of each vertebra a 

 similar spur is directed backward and fits into the notch of the succeed- 

 ing vertebra. At each end of the lower surface of each vertebra is an 

 inferior zygopophysis ; the anterior one projecting over the posterior 

 one of the next preceding vertebra. These are larger in Megalaspis 

 than in the others. 



In Megalaspis the neural and haemal spines of the tail region be- 

 come flattened and lie flat each against the surface of the next succeed- 

 ing vertebra, restricting its movement to a lateral one. From the upper 

 and lower surface of each caudal peduncle vertebra a sharp longitudinal 

 wing is developed laterally, and from the side of each of the 5 or 6 

 vertebrae preceding the third in front of the caudal a flat spine is pro- 

 duced, forming a broken caudal keel. The caudal fin rays are very 

 deeply cleft at the base, and so broadly clasp the hypural bone as to 

 nearly hide it from sight. Caranx approaches this condition, and to a 

 less degree Trachurops, Trachurus and Decapterus. In Megalaspis the 

 inferior vertebral foramina are greatly enlarged. These attain their 

 greatest size in the bases of the last parapophyses, where the largest is 

 equal in diameter to the least width of the vertebral centrum just 

 above it. Caranx, Chloroscombrus and Gnathanodon show this con- 

 dition to a less degree; Citula, Alectis and Vomer have the inferior 

 foramina more or less developed in the bases of the haemal arches and 

 parapophyses, while in Decapterus, Trachurops, Trachurus and Selene 

 the foramina are confined to the haemal arches. 



With the exception of Seriola and Naucrates and to a much less 

 degree Trachurops, Trachurus and Decapterus the first interhaemal is 

 very large and strong, and is very solidly attached to the equally strong 

 first haemal process. Often this stay is further reinforced behind by 

 other interhaemal bones, which incline forward against it. 



The interspinous rays of the dorsal spines about coincide in num- 

 ber with the neural processes, but those of the dorsal and anal rays are 

 two or three to one of the neural and haemal processes. 



The first two vertebrae bear epipleurals only. The other anterior 

 epipleurals are always on the ribs. The anterior ribs are attached 

 directly to the vertebral centra, sometimes, as in Trachurops, Caranx 

 and Decapterus, in deep pits, whose edges are raised above the body 

 of the centra. Scomberoides and Oligoplites are peculiar in having the 

 ribs attached high on the centra, remote from the parapophyses, except 

 the posterior two pairs, which drop down to the tips of the para- 

 pophyses. 



