The Osteology of the Scombridce. 87 



total of 31 with the hypural. The parapophyses are not developed 

 anteriorly. On the eleventh abdominal vertebra they first appear, 

 but are here joined to each other to form a hsemal arch. Anterior 

 to this on two or three vertebrae the edges of the socket into which the 

 rib fits is slightly produced into a crater-like rim, but no developed 

 process is present. On the first three hsemal arches no spine is 

 present, but on the arch of the last abdominal vertebra the spine is 

 long and similar to those on the anterior caudal vertebrae. Conse- 

 quently aside from the fact that the abdominal vertebrae bear ribs, 

 and the first caudal vertebrae bear the anal fin there is nothing to 

 differentiate the abdominal vertebrae from the caudal. The inferior 

 foramen is present in the base of the haemal spine of the last 

 abdominal vertebra, and in most of the caudal vertebrae. The last 

 two or three vertebrae are not abruptly shortened. On the anterior 

 caudal and posterior abdominal vertebrae each antero-zygopophysis 

 reaches forward and forms a semi-inclosed space behind and below 

 each inferior vertebral foramen. The first two vertebrae bear epi- 

 pleurals only; the first ribs being on the third vertebra. The ribs 

 are flattened and are directed backward so that they lie close to each 

 other. When the haemal arches develop, the ribs drop down to their 

 tips and the bases of each pair of ribs are thus brought in contact. 

 The epipleurals are attached directly to the vertebrae, and anteriorly 

 their bases are in contact with those of the ribs, but posteriorly they 

 hold their position at the bases of the haemal arches, while the ribs 

 drop down to the haemal spines. The epipleurals are present back to 

 opposite the posterior part of the anal fin. The intemeurals of the 

 spinous dorsal are much expanded at the upper end, but the baseosts, 

 one of which is in front of each spine, are so broad they extend later- 

 ally far over the interneurals, and form a bony buckler that is visible 

 under the skin of the undissected specimen. A long baseost extends 

 between each of the finlets behind the dorsal and the anal fin. The 

 first interhaemal is not enlarged. The caudal rays are deeply divided 

 and so fit over the hypural plate that they cover it more than half 

 from sight. 



The elements not mentioned here are as they normally are in the 

 great majority of spiny-rayed fishes, 



