length in larvae up to notochord flexion and thereafter 

 increases to an average of 58%. Head length also in- 

 creases during the larval period from an average of 35% of 

 body length in preHexion larvae, to 36% in larvae under- 

 going flexion, to 37% in postflexion larvae. The eye is 

 moderate in size and averages 30% of the head length 

 during the larval period with no trend of relative increase. 

 Snout length averages 35% of the head length over the 

 letrval period. 



The bases and blades of the pectoral fins are well dif- 

 ferentiated in the 2.8-mm specimen of Sparta (1942). 

 The short round blade portion of the pectoral fin is 

 another feature held in common with many species of 

 Sebastes. The paucity of specimens of H. dactylopterus 

 precluded staining for osteological study; however, the 

 size at formation of pectoral fin rays can be observed in 

 unstained specimens. Pectoral rays begin to appear when 

 the larvae are about 4.0 mm long and the last (lower- 

 most) rays have differentiated at about 8.0 mm. The 

 usual number of rays is 19. The pelvic fin buds appear in 

 larvae about 6.0 mm long. The rays begin differentiating 

 in 7-mm larvae, and the full complement of one spine 

 and five rays is present in the 8.6-mm specimen. 



The hypural anlage of the caudal fin is apparent in 3- 

 mm larvae and the elements and principal caudal rays 

 begin to differentiate in 4-mm larvae. The full com- 

 plement of principal rays (8 + 7) is present in 7-mm lar- 

 vae. Notochord flexion occurs at a relatively large size 

 (6.0 to 8.0 mm) as in Sebastes and is another character 

 held in common by the two genera. The dorsal and anal 

 fins begin to form simultaneously in larvae about 6.0 mm 

 long, but the full complements of XII, 11 or 12 dorsal rays 

 and in, 5 anal rays are not present until 8.6 mm. 



Larvae of H. dactylopterus have a distinctive pigment 

 pattern that is established in larvae less than 3.0 mm 

 long. On the head, a group of melanophores is present on 

 the lower jaw and above the brain. The dorsolateral sur- 

 faces of the gut are covered with a solid shield of pig- 

 ment which enlarges ventrally with continued develop- 

 ment. Several superficial melanophores are present on 

 the trunk just above the axillary region. The medial sur- 

 face of the pectoral fin base is solidly pigmented and fine 

 melanophores are located at two regions on the blade of 

 the fin, some near the distal margin and another group at 



the basal region of the fin blade. A group of 

 melanophores is present at the ventral midline of the tail 

 just anterior to where the caudal fin will form. This uni- 

 que pattern of pigmentation remains essentially un- 

 changed throughout the entire larval period. 



Distribution. — Adults of H. dactylopterus have a 

 complex distribution. Eschmeyer (1969) recognized two 

 Atlantic subspecies, H. d. dactylopterus and H. d. lahil- 

 lei, with the former composed of four separate pop- 

 ulations (northeastern Atlantic and Mediterranean, Gulf 

 of Guinea, South Africa, and northwestern Atlantic). 

 The subspecies H. d. lahillei is found off Uruguay and 

 Argentina. The 6.0- and 6.2-mm specimens in the series 

 are from Discovery station 714, off Uruguay, and thus are 

 larvae of H. d. lahillei. They are not distinguishable from 

 larvae of H. d. dactylopterus. 



Sebastolobua Gill 



Literature. — Pearcy (1962) described the floating egg 

 masses, the developing embryos, and the newly hatched 

 larvae oi Sebastolobus. The larvae, pelagic juveniles, arid 

 early demersal juveniles of S. altivelis and S. alascanus 

 are described and illustrated in Moser (1974). Larvae of 

 the other species in the genus, S. macrochir, of the north- 

 western Pacific, have not been described; however, 

 pelagic juveniles of this species are described and illus- 

 trated in Moser (1974). 



Distinguishing features. — Early Sebastolobus lar- 

 vae (up to 6 mm) can be distinguished from those of all 

 other genera of eastern Pacific Scorpaenidae on the basis 

 of pigmentation. Sebastolobus larvae of this size range 

 are unique in having two large melanistic blotches about 

 midway along the tail, one at the dorsal midline and one 

 at the ventral midline. These are sometimes expanded to 

 form a solid band on the tail (Fig. 24). Early larvae of all 

 other eastern Pacific scorpaenid genera have a series of 

 melanophores along the ventral midline of the tail, and 

 in some species of Sebastes, an opposing row is present at 

 the dorsal midline. The large tail blotches of 

 Sebastolobus disappear in larvae between 4.2 and 6.4 

 mm. Soon after the loss of these large tail blotches the 

 larvae develop prominent crestlike parietal ridges that 

 terminate in double spines, the posterior (nuchal) spine 

 being longer and more prominent than the anterior 

 (parietal) spine (Fig. 24). Of the other eastern Pacific 

 scorpaenid genera, only the larvae of Scorpaenodes have 

 parietal ridges and spines like Sebastolobus. If two 

 spines are present on the parietal ridges of other genera, 

 the anterior spine is always longer and more prominent 

 than the posterior. Sebastolobus larvae may be dis- 

 tinguished from those of Scorpaenodes on the basis of a 

 melanistic shield, which covers the dorsolateral surface 

 of the gut in the former and is absent in the latter. Lar- 

 vae of Sebastolobus smaller than 10.0 mm could not be 

 identified to species. Larvae larger than this can be iden- 

 tified to species by a combination of characters that are 



40 



