398 



Fishery Bulletin 89(3). 1991 



Figure 7 



Xystreurys liolepis larvae (P = preopercular spines): (A) 2.0 mm YS (LACM 044 

 OB 15 OB 02P), (B) 2.1 mm YS (050 87 22 OB 02S), (C) 2.2 mm NL (LACM 044 87 

 36 OB 02S), (D) 2.8 mm NL (LACM 044 OB 22 OB 01S), (E) 4.2 mm NL (LACM 

 050 87 22 OB 02S). 



and scattered dorsolateral melano- 

 phores of flexion larvae extend 

 from about the first to the 29th or 

 30th myomere. Ventrolateral me- 

 lanophores are located from approx- 

 imately the 10th to the 30th myo- 

 mere, and concentrated pigment 

 along the postanal ventral margin 

 is found from the vent to the last 

 myomere (Fig. 8A). Dorsolateral 

 and ventrolateral melanophores 

 spread over the trunk and tail of 

 postflexion larvae on all but the last 

 six to eight myomeres, and several 

 dense melanophores form posterior- 

 ly along the lateral midline (Figs. 

 8B,C). 



Internal melanophores form on 

 the dorsal surface of the notochord 

 during the preflexion stage, but this 

 pigment is obscured by thick mus- 

 culature and heavy external pig- 

 mentation. 



Pigment typically is present along 

 the peritoneum and ventral midline 

 of the gut at the end of the yolksac 

 period. The gut of late-stage pre- 

 flexion larvae is heavily pigmented, 

 especially along the ventral margin 

 from the cleithrum to the anus (Fig. 

 7E). Ventral margin pigment ex- 

 tends anterior to the cleithra in 

 postflexion larvae (Fig. 8B). 



Yolksac and preflexion larvae 

 have few melanophores on the head 

 and snout. Pigment develops on the 

 upper and lower jaws, and upper 

 palate of flexion stage larvae. 



Larval comparisons Myomere 

 or vertebral counts (34-36, Para- 

 lichthys californicus and 37-39, 

 Xystreurys liolepis) will separate 

 the larvae of P. californicus and 

 X. liolepis, but these counts can be 

 difficult to make, especially on small 

 or damaged specimens. Morpho- 

 logical and pigment characters that 

 will facilitate separation of the lar- 

 vae of the two species until meta- 

 morphosis are given in Table 6. 

 Visiblity of internal notochord pig- 

 ment is the primary character for 

 separation of post-yolksac larvae. 

 Presence of sphenotic spines and 



