HOUDE; DEVELOPMENTAL ABNORMALITIES OF ^rhirus linealus 



Figure 3. — Left side (upper photo) and right side (lower 

 photo) of 32.6 mm TL abnormal Acliirus tineatus reared 

 in the laboratory. Abnormalities include ambicolora- 

 tion, hooked dorsal fin, partial eye migration, and 

 presence of a left pectoral fin. 



Figure 4. — Right side of head of 34.8 mm TL abnormal 

 Achirus lineatus reared in the laboratory. Abnormal- 

 ities include ambicoloration, hooked dorsal fin, and 

 presence of a left pectoral fin. Eye migration nearly 

 complete. 



ygiophores appeared normal and articulated with 

 the supraoccipital serrations, but were directed 

 away from the neurocranium at an angle of 

 about 20°. No fleshy connection was established 

 between the doi'sal fin and the incompletely ro- 

 tated prefrontal complex. Hooked dorsal fins 

 and eye migration failure are associated (Fig- 

 ures 2 and 3), but the hooked condition can 

 also be present when eye migration is nearly 

 normal (Figure 4). 



ranged from almost total failure of migration 

 (Figures 2 and 7) to various stages of partial 

 or nearly complete migration (Figures 3 and 4) . 

 All individuals with this abnormality also had 

 hooked dorsal fins and were ambicolored or par- 

 tially albinistic. In normal A. lineatus eye mi- 

 gration began at about 3.5 mm TL and was com- 

 plete at 6.5 mm TL (Houde et al., 1970). 



REVERSAL 



EYE MIGRATION 



Migration (rotation) of the left eye was in- 

 complete in 17 specimens. The abnormality 



A single reversed specimen was reared. This 

 specimen was not included among the 31 treated 

 in Table 1 because it was preserved before meta- 

 morphosis was completed. Reversals among the 



541 



