FISHERY BULLETIN: VOL. 72, NO. 4 







Figure 8. — Opisthonema oglinum juvenile 30.8 mm standard length. 



size and became more heavily ossified; at about 

 14 mm, small teeth v^ere found on the ventral 

 edge of the maxillaries and the anterodorsal 

 edge of the dentaries. Concommitantly, the hyoid 

 apparatus continued to develop steadily, particu- 

 larly the ceratohyals and hypohyals, which were 

 quite distinct and slightly ossified by 14 mm. 

 By about 17 mm, the two supramaxillaries were 

 differentiated and partly ossified but had not 

 obtained their characteristic adult shapes. The 

 premaxillaries also were partly formed and ossi- 

 fied as two distinctly separate units close to the 

 anterior tips of the maxillaries. By 19 mm, the 

 articular was well developed but not fully ossi- 

 fied. The posterior supramaxillary was almost 

 completely ossified but not the anterior supra- 

 maxillary. Maxillaries maintained an ossified 

 posterior edge (the region of growth), and the 

 teeth on the ventral edges were still prominent. 

 The ceratohyals and urohyal were more ossified, 

 and two small centers of heavy ossification were 



present in the hypohyals. One structure of interest 

 was the presence of teeth on a few specimens 

 on the basihyal. In a 12.0-mm specimen, two 

 large erect teeth were noted; a 15.6-mm specimen 

 had one such tooth, which was also present on 

 a 17.1-mm specimen. No such teeth were evident 

 on a 25.9-mm specimen, indicating that these 

 teeth may be variable and limited in occurrence. 

 Houde et al. (1974) noted the presence of these 

 temporary teeth in Harengula. The branchio- 

 stegals ossified in the following sequence: fourth 

 branchiostegal slightly ossified at 15.5 mm; fourth 

 well ossified at 17.1 mm; fourth, third, and 

 second ossified; first visible as cartilage; fifth 

 and sixth not visible at 19.7 mm. By the time 

 specimens reached 24 mm, six well-ossified 

 branchiostegals were present, the supramaxil- 

 laries were ossified but the posterior supra- 

 maxillary had not reached a complete adult 

 shape, all the hyals were partly ossified, the 

 well-developed premaxillaries were ossified and 



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