FISHERY BULLETIN: VOL. 81, NO. 4 



Samples were preserved in 5 a neutral Formalin 1 . 

 Eggs were cleared over glycerin according to the 

 method of Galat (1972). All developmental rates are 

 at 5°C. Larvae were fed wild plankton which were 

 obtained with a #20 mesh net, and after a month 

 brine shrimp nauplii were added to the diet. 



Drawings and descriptions are from all series. All 

 drawings were done with the aid of a camera 

 lucida. 



RESULTS AND DISCUSSION 



The egg of the longhorn sculpin was spherical and 

 adhesive. The chorion was leathery and translucent. 

 Egg color was variable but consistent within a single 

 female. Eggs were green, red, and reddish brown. 

 Morrow (1951) reported variable coloration of long- 

 horn eggs. Lund and Marcy (1975), Bigelow and 

 Schroeder (1953), and Westin (1968) described 

 various egg colors of M aenaeus, M. scorpius, and M. 

 quadricornis, respectively. Egg color remained con- 



'Reference to trade names does not imply endorsement by the 

 National Marine Fisheries Service, NOAA. 



stant throughout development. Subsequent state- 

 ments refer to morphological changes. 



Unfertilized, water-hardened eggs: These eggs of 

 longhorn sculpins were spherical with a mean 

 diameter of 2.21 mm and a range of 2.1-2.3 mm. 

 Mean yolk diameter was 2.10 mm (range 2.0-2.2 

 mm). The number of oil droplets was variable; some 

 eggs had several small droplets scattered throughout 

 the yolk, whereas others had only two or more large 

 droplets. Perivitelline space was less than one-tenth 

 of the egg capsule radius. Surface of the yolk capsule 

 was slightly irregular. Chorion was colorless, translu- 

 cent, and leathery (Fig. 1A). 



Two-cell stage: Initial cleavage was meroblastic 

 and was first observed at 8.0 h. Most eggs had 

 cleaved by 8.5 h. Blastomeres were about equal in 

 size and slightly elevated. Egg capsules had a mean 

 diameter of 2.18 mm (range 2.1-2.3 mm). Yolk cap- 

 sule had a mean diameter of 2.06 mm (range 1.9-2.1 

 mm). The number of oil droplets was variable. 

 Perivitelline space was about one-tenth of the radius 

 of the egg capsule. Yolk surface was slightly cor- 

 rugated (Fig. IB). 



Four-cell stage: Second cleavage was perpen- 



0.5 mm 

 I 1 



Figure 1. —Early development of the eggs of the longhorn sculpin, Myaxoci'phalusoctodi'cemspinosus, artificially propagated in the laboratory: 

 Ai unlertilized water- hardened egg, 2.21 mm; B) fertilized egg, 2.19 mm, 2-cell stage (8.5 h); C) 4-cell Mage. 2.15 mm 1 10.5 h); I)) 8-cell stage. 

 2.22 mm (14.(1 h); E) lti-cell stage, 2.15 mm (2(1.0 h); F) 32-cell stage. 2.21 mm (24 hi; stale 0.5 mm. Measurements refer to mean egg 

 capsule diameters. 



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