Figure 23.— Various stages of development of egg and larvae of Auxis (Mito 1961); 1) Pelagic egg, 7'j h after 

 collecting. 1.04 mm in diameter, oil lobule 0.26 mm; 2) 29-myotome stage, 94 h after; .3) 10'2 h after; 4) 

 14'? hr after, shortly before hatching (24'-27"C); 5) empty egg capsule; 6) larva just hatched, 2.70 mm TL, 

 myotomes 11 + 32 = 43; 7) larva 16'; h after hatching, 3.68 mm TL, myotomes 9 + 31 = 40; 8) larva 30 h 

 after. 3.58 mm TL, myotomes 9 + 31 = 40; 9) larva 42'2 h after, 3.92 mm TL, myotomes 9 + 32 = 41; 10) 

 larva .Vi h after. 3.75 mm TL, myotomes 8 + 31 = 39. 



In addition to the gill raker counts (38-43 for A. 

 thazard and 43-49 for A. rochei), the form of the free 

 parapophyses is a useful feature of the axial skeleton for 

 separating Auxis to species. Watanabe (1964) deter- 

 mined that in A. thazard, the free parapophyses are 

 long, extend downward and almost touch the haemal 

 spine of the preceding vertebra whereas in ^4. rochei they 

 are short. This difference in length of the parapophyses 



IS particularly evident on specimens of 111 mm or more 

 (Figs. 24, 25). 



Four other characters used by Watanabe (1964) in- 

 clude: 1) the number of the vertebra on which the first 

 free parapophysis occurs, 2) the number of the vertebra 

 on which the first inferior foramen occurs, 3) the ratio of 

 the length of the caudal to the precaudal vertebra, and 

 4) the ratio of the body height at the origin of the anal 



29 



