(2) the junction of the anterior and posterior roots;
(3) the relations of the segmental ducts to the segmental involutions and the alternation of calibre in the segmental tube;
(4) the germinal epithelium lining the body-cavity.
[1] The apparent structure in the sheath of the notochord in this and the succeeding figure is merely the result of an attempt on the part of the engraver to represent the dark colour of the sheath in the original figure.
EXPLANATION OF [PLATE 13]. (X. p. 361.)
Complete List of Reference Letters.
al. Alimentary tract. ao. Aorta. c. Connective tissue. cav. Cardinal vein. ch. Notochord. ep. Epiblast. ha. Hæmal arch. l. Liver. ll. Lateral line. mc. Mucous canal of the head. mel. Membrana elastica externa. mp. Muscle-plate. mp´. Muscles of muscle-plate. na. Neural arch. nl. Nervus lateralis. rp. Rib process. sd. Segmental duct. sh. Sheath of notochord. spc. Spinal cord. spg. Spinal ganglion. syg. Sympathetic ganglion. um. Ductus choledochus. v. Blood-vessel. var. Vertebral arch. vb. Vertebral body. vcau. Caudal vein. vin. Intestinal branch of the vagus. vop. Ramus ophthalmicus of the fifth nerve. x. Subnotochordal rod.
Fig. 1. Section through the anterior part of an embryo of Scyllium canicula during stage L.
c. Peculiar large cells which are found at the dorsal part of the spinal cord. Sympathetic ganglion shewn at syg. Zeiss A, ocul. 1.