由负鼠肩部肌肉发生观察肢部肌肉与肌节之关系

DEVELOPMENT OF THE SHOULDER OF OPOSSUM,Didelphys virginiana,IN RELATION TO ORIGIN OF LIMB MUSCULATURE.

关於肢部肌肉之来源究竟由何部中胚层发生,迄今犹为一争论问题;第一:肢芽内之间充细胞,早期时紧密排列,极少差异,颇难从单纯观察上决定骨肉与皮层之分界。第二:从神经支配上着眼,似可确定肢部肌肉系由颈部或腰部肌节向腹侧伸入肢芽而成,但对高等脊椎动物肢芽之发生的研究工作中从未见有肌节伸入肢芽现象。Patten所建议由相关体节伸入肢芽纯属理想。第三:甚多胚胎学者及实验胚胎学者研究所得之结果甚不一致,有者能证明肢芽之发生与肌节有相互关系如Field,Rylkoff,Mollier及Sewertzoff等,有者则否定此种关系之存在,如Patterson,Byrnes,Lewis,Harrison及Detwiler等。因此由肢芽发生程序上观察肢芽内生肌间充组织之来源,当有其一定价值。

It has long been controversial whether or not the limb musculatureoriginates from the myotome.On the basis of morphological evidence foundin the study of the development of the shoulder of the opossum,Didelphysvirginiana the present paper presents some facts in support of the latter view.In the early stage of development,there is a set of venous network,theborder veins,interposed between the primorial dermis of the limb bud on theone hand and the premuscular and precartilage anlagen on the other.Theborder veins can be traced in subsequent stages of development to the subcutaneous veins of the adult.Furthermore,the celluler structures of the primordialdermis and the two anlagen are found to be quite different,while the twoanlagen themselves are close resemble except in their degree of staining.Theconnections of the primitive dermis with the dermatome and the connectionsof the precartilage and premuscular anlagen with the somatopleure have beendefinitely observed.The above structural relationships have been observed alsoin the hindlimb of the opossum and in other vertebrates except fish.Itseems justified to conclude thet the dermis and subcutaneous tissue of thelimb bud orginate from the dermatome and that the skeletal muscular elements originate from the somatopleure.