COIIPAKATIVE STUDY OP SCOMBROID FISIIES. 431 



bcnitos, the cutaneous veins clo not unite directly with the Cuvieri:in duct, but 

 form liopatic pirtal veins. In bouitos the vnsciilftr plexus is also foimd in tlio 

 haemid canal. Blood vessels in the air- bladder belong to the visceral viuseulav 

 system. 



In primitive timnies tlie kidneys are mora or less ring-shaped, jiLst Miind 

 the head, and around tlio phaiyngoal mxiscles. In the otlmr tunnies the 

 kidneys are produced more or less liohinil, and in bonitos they ara elongated 

 nearly to the end of the abdominal cavity. Posterior portions of the kifhaeys 

 lie chiefly on the roof of the abdominal cavity but, in the haemal canal too 

 we find a continuous or sometimes small discontinuous masses of a kidney-like 

 brownish substance with minute black spots. 



Skeleton firm, solid, and comparatively light. Skull firmly (rousolidated. 

 The dorsal surface of the skull is entirely covered with the Lateral muscle and 

 there we find paired non-ossified portions, except in the genus Avxis. On 

 the ventral side of the skuU we find many deep grooves for the insertion 

 of opercular muscles. The posterior end of the parasphenoid is more or less 

 tubular. Subcranial canity is very high. Lower piece of the postclavicle is 

 not flat, the broad proximal part mfiking nearly a right angle with the naiTow 

 distal part, and these two parts ai-e in two difierent planes. Tlie distal part 

 is very short in nuiuy cases. Clavicular ligament is inserted in tlie first 

 vertebra not to the skull. 



Vertebrae are compact and rich in grooves and ridges, so that they are 

 light and firm. The total numter of vei-tebrae is alwaj-s 39, except in the 

 genus Katsmocmus which has 41. Tliey difier from each other in form, processes, 

 etc, in difierent parts of the vertebral column. Neural and haemal processes 

 ■'ire more or less Laterally compressefl. The first neural process is remarkably 

 feeble. 



Fishes of this order seem to liave their own temporatm-e, more or less 

 higher than the temperatm-a of the water in wliich they live. Tliey are 

 voracious, ^jeLagic fish, swimming very fast, and feeding on small fish, calamaries, 

 and medium sized plankton. Foimd in temperate and tivipical seas. They 

 spawn in off-shore grounds and gi'ow there. They are very energetic and 

 powerful, therefore specially long and strong implements ai-e required for catch- 

 ing them. 



