Figure 32.— Stations at which larvae of Scorpaena guttata were 

 talcen on CalCOFI cruises during 1966. Solid circles indicate stations 

 where number of larvae exceeded mean (7.4) for all positive stations. 

 Area of complete grid is outlined (see Ahlstrom 1961 for complete 

 grid). 



The gut is compact and increases in relative length 

 during the larval period. Snout-anus length averages 50% 

 of body length prior to notochord flexion, 53% during 

 flexion, and 61% following flexion. Head size is moderate 

 and increases relative to body length during develop- 

 ment. Head length averages 28% up to the beginning of 

 notochord flexion, 32% during flexion, and 38% fol- 



lowing flexion. Snout length and eye diameter show no 

 change relative to head size and average 32% and 33% of 

 head length, respectively. 



The fan-shaped pectoral fins are similar in size to 

 those of S. guttata. They increase in relative length from 

 an average of 12% of body length in preflexion larvae to 

 16% during flexion, and 21% following flexion. Depth of 

 the fin base shows a more gradual relative increase of 

 14%, 15%, and 17% for the three stages. Pectoral fin rays 

 begin to ossify in 3-mm larvae and the full complement 

 of 19 to 20 rays is present in 4-mm larvae. The pelvic fins 

 begin to form in 4-mm larvae and reach a maximum of 

 18%) of the body length in our largest larva. Ossification 

 is initiated in 4-mm larvae and the full complement of I, 

 5 rays is present at 6.0-mm length. 



The hypural anlagen of the caudal fin appear in lar- 

 vae about 2.5 mm long. They begin to ossify when the 

 larvae reach 4.0 mm and the large superior and inferior 

 elements are well ossified at a length of 6.0 mm. Primary 

 caudal rays begin to ossify in 3-mm larvae and the full 

 complement of 8 -t- 7 rays is present at about 4.0-mm 

 length. Secondary caudal rays begin ossifying at about 

 4.0-mm length and there are 5 superior and 5 inferior 

 rays present in our largest stained specimen (6.0 mm). 



The dorsal and anal fins begin to develop simul- 

 taneously in larvae about 4.0 mm long. Ossification is in- 

 itiated immediately thereafter and the larvae larger than 

 5.3 mm have III, 5 anal rays and XII, 8 dorsal rays. 



The larvae of Scorpaena Type A differ from those of S. 

 guttata chiefly in the pattern of melanophores. As in ear- 

 ly larvae of S. guttata, those of S. Type A have 

 melanophores along the dorsolateral surfaces of the gut, 

 along the ventral midline of the tail, and on the pectoral 

 fins. The particular arrangement of melanophores on the 

 tail and pectoral fins is distinctly different in the two 

 forms and is a useful means of separating them. In Type 

 A larvae the ventral midline series extends along the en- 

 tire length of the tail from above the anus posteriad to 

 the hypural anlage of the caudal fin. In larvae of S. gut- 

 tata, the series is confined to the posterior half of the tail. 

 Accordingly, there are more melanophores in this series 

 in Type A; the range for preflexion larvae is 8 to 14 and 

 for larvae undergoing flexion is 4 to 8. Ventral tail 

 melanophores are not present in postflexion larvae. The 

 melanophore pattern of the pectoral fin is similar in lar- 

 vae of S. Type A and S. guttata up to about 3.0 mm in 

 length. At that size, a region of darker pigmentation 

 develops at the ventral aspect of the fin in Type A. This 

 area of darker pigment remains detectable from the sur- 

 rounding pigment in larvae up to about 6.0 mm in 

 length. This pigment does not develop in larvae of S. gut- 

 tata. As in S. guttata, pigment begins to develop on the 

 medial surface of the fin base at about 3.0 mm in length 

 and intensifies during the remaining larval period. In 

 Type A larvae of about 4.0-mm length the dorsal and up- 

 per posterior margins of the fin begin to lose 

 melanophores. This clearing becomes more extensive 

 with further development and in the largest larvae the 

 membranes of the most dorsal three rays and the pos- 

 terior one-third of the fin are clear. In S. guttata only a 



58 



