マアジの成長に伴う頭蓋骨の異常発達

抄録

As far as known, abnormal development of the cranial bones in teleostei are described about three species, Thunnus thynnus, Chrysophrys major and Muraenoesox cineures. The author examined the morphological changes of the cranial bones of “Jack-mackerel” Trachurus japonicus, with the growth from 4 cm to 34 cm in body-length.
The purpose of this article is to record with brief description the abnormal develop ment of the cranial bones in this fish. The remarkable expantion of supraoccipital bone in the cranium is noticed as shown in Fig. 1, and its gradual change is seen to be accomplished from 22 cm to 25 cm in body-length as in Table 1.