superior and 7 inferior rays is present in a 4.6-min larva. 

 The procurrent caudal rays begin to ossify in 5-mm lar- 

 vae and the full complements of 4 superior and 4 inferior 

 rays are present in 6-mm larvae. 



The pelvic fin appears in 4-mm larvae and increases in 

 length to 13% of body length at the completion of noto- 

 chord flexion. Fin length averages 18% of body length for 

 the remainder of the larval period. The rays begin to 

 ossify in 4-mm larvae, and the full complement of 1 spi- 

 nous ray and 5 soft rays is present at 4.6 mm in length. 



The dorsal and anal fins begin to develop simul- 

 taneously in 4-mm larvae. Ossification of the rays begins 

 in 5-mm larvae and the full complements of XIII, 9 (10) 

 dorsal rays and III, 5 anal rays are present before the lar- 

 vae reach 6.0 mm. 



Pigmentation is sparse in S. xyris larvae. The smallest 

 larvae in the collection have a series of 12 to 18 

 melanophores along the ventral midline of the tail, from 

 the junction of the gut to the hypural anlage. They also 

 have a patch of melanophores along the ventral midline 

 of the gut and several melanophores on the terminal sec- 

 tion of the gut. Also, there is an embedded blotch just 

 dorsal to the axilla and the distal region of each pectoral 

 fin is covered with fine melanophores. 



As development proceeds some of this original pig- 

 ment pattern is lost. The series on the ventral midline of 

 the tail is lost before the larvae reach 4.0 mm. The 

 melanophores at the ventral midline of the gut are lost in 

 larvae between 4.0 and 4.5 mm. The patch median to the 

 axillary region enlarges to form a shield over the gas 

 bladder and is visible throughout the larval period. 



Just before transformation, a group of melanophores 

 appears on the opercle and preopercle. Transforming 

 specimens from bottom collections have a striking mot- 

 tled pattern on the head and body. In some, the distal 

 mtirgin of the pectoral fin is still melanistic. 



Distribution. — Scorpaenodes xyris is a coastal warm- 

 water species. Adults have a latitudinal range from Peru 

 northward to San Clemente Island, Calif., and occur off 

 islands such as Guadalupe and the Galapagos (Miller 

 and Lea 1972). CalCOFI surveys show that the larvae oc- 

 cur throughout the lower two-thirds of the Gulf of 

 California. On the outer coast, S. xyris larvae were found 

 only as far north as line 117 (about lat. 28°N) off Punta 

 Eugenia. The planktonic collections of the E ASTRO PAC 

 expedition show that S. xyris larvae occur from lat. 20°N 

 to lat. 20°S along a coastal band (Fig. 30). Larvae oc- 

 curred in small numbers in both CalCOFI and the 

 eastern tropical Pacific hauls. The largest number taken 

 on any haul was seven, and three-fourths of the positive 

 hauls had a single larva of S. xyris. 



Larvae were taken on all CalCOFI cruises in the Gulf 

 of California (Fig. 30). More larvae were taken in June 

 than in the other months (February, April, December), 

 thus suggesting a summer spawning peak in this region. 

 On EASTROPAC expeditions, the number of occur- 

 rences was about equal on the winter cruises (February- 

 April) and the summer cruises (July-September). 



SO'Pl'iMMijMM 



• • 



III. I J.I 1,1.1.1,1, lilil.l.l.lil.M.lilil I.lilililil.l. 1, 1, 1,1, 1 H 



Figure 30.— Stations at which larvae of Scorpaenodes xyria were 

 taken on CalCOFI cruises (triangles) during 1956 and 1957 and 

 EASTROPAC expeditions (dots) during 1%7 and l%g. 



Scorpaena Linnaeus 



Literature. — The early stages of two North Atlantic- 

 Mediterranean species of Scorpaena, S. porcus and S. 

 scrofa, were described by Raffaelle (1888) and Fage 

 (1918). More thorough descriptions of the egg, larval, and 

 juvenile stages of these two species and of the eggs and 

 larvae of S. notatus were given by Sparta (1941, 1942, 

 1956). The latter paper includes a color plate. The early 

 developmental stages of the sculpin, Scorpaena guttata, 

 of California and Baja California were described from 

 specimens cultured in aquaria (Barnhart 1932; David 

 1939; Orton 1955). These authors described the egg 

 masses, developing eggs, and larvae up to the stage of 

 yolk exhaustion (about 3.0 mm body length). 



Distinguishing features. — Scorpaena larvae are easi- 

 ly distinguished from Sebastes and Sebastolobus by 

 myomere count, Scorpaena having 24, Sebastes having 

 26 or more, and Sebastolobus having 28 or more. Scor- 

 paena differs further from Sebastolobus in having a row 

 of melanophores along the ventral midline of the tail, as 

 opposed to a single dorsal and ventral blotch, and in hav- 

 ing nonbifurcate parietal ridges. This latter character 

 also separates Scorpaena from Scorpaenodes. Scorpaena 

 larvae develop a moderately long pair of parietal spines 

 that reach their greatest relative length at about the 

 completion of caudal fin formation. A small nuchal spine 

 forms subjacent to each parietal spine. Scorpaena may 

 be separated from Pontinus on the basis of gut pigmen- 

 tation. Scorpaena larvae develop a melanistic shield over 

 the dorsolateral surface of the gut, whereas Pontinus lar- 

 vae have a deeply embedded blotch above the axillary 

 region which, as in Scorpaenodes, enlarges to cover the 



54 



