無尾両生類の変態中の筋に及ぼすthyroxineの影響について

抄録

The author investigated the relation between the concentration of thyroxine and the transformation of the anuran mouth-opening muscles (Mm. levatores hyoidei, espicially M. orbito-hyoideus of the larva to M, depressor mandibulae of the adult) during metamorphosis of the Japanese toad (Bufo vulyaris japonicus) by dissection under the stereoscopic microscope and by tinctorial examination on serial sections.
Summarized results are followed.
1) Treatment of toadpoles with thyroxine in high concentration (in more 0.25ppm) produces rapid, uncoordinated and atypical metamorphosis (monster).
In this case, thl larval muscle does not transform to the M. depressor mandibulae its form remaining as it was, but microscopically the new-birth of myoblasts of the adult muscle is found.
2) Treated in very low concentration (in less 0.00, 5ppm), the specimen is scarcely differd from untreated one in the said muscles.
3) In moderate concentratien, some disorders as followed are found;
(A) lengthening of the M. depressor mandibulae,
(B) forming of digastric muscle of the muscle,
(C) remaining of M. suspensorio-angnlaris,
(D) remainimg of M. suspensorio-hyoideus,
(B) remaining of M. quadrato-angularis,
(F) remainiag of degenerating connective tissue-like substance,
(G) abnormal form of Cattilago quadrati,
(H) existence of combined disorders of above-mentioned disorders,
4) From these results, the author thinks that thyroxine accerate the new-birth and development of the new muscle of adult, rather than degeneration and disappearance of the old muscles of larva for metamorphosing mouth-opening muscles of anurans.