48 F. W. THYNG 



approximately from a level of the twelfth thoracic to the second 

 lumbar nerve, and appears externally as an oval, lobulated body. 

 It consists of approximately eight branches arising from the ceph- 

 alic extremity of the ureter, the renal pelvis. Each branch 

 ends in a bilobated ampulla which is surrounded by condensed 

 'nephrogenic tissue.' The ureter as it leaves the developing 

 metanephros, extends at first caudally and medially in the ven- 

 tral part of the dorsal body wall. It then passes ventrally in the 

 lateral parieties and opens into the extreme lateral wall of the 

 anlage of the bladder. The ureteral orifices are slightly cepha- 

 lad of those by which the Wolffian ducts communicate with the 

 urogenital sinus. 



Genital ridges. The ovaries are two compact, longitudinal pro- 

 tuberances projecting from the medial borders of the Wolffian 

 bodies. They taper at either extremity, more gradually at the 

 cephalic than the caudal. The cephalic end of the left ovary 

 (G.R.) is partly hidden from view in plate 2 by the Wolffian body, 

 but it does not extend quite to the cephalic pole of the latter. 

 The caudal end of the ovary is on a level with that of the meso- 

 nephros by w^hich it is hidden in the drawing. The cephalic 

 region of each ovary is deeply marked by infolding of the germ- 

 inal epithelium. 



DUCTLESS GLANDS 



The right suprarenal is shown in plate 4, the spleen in plate 2. 

 The thyreoid, thymus, and parathyreoid glands are described in 

 connection with the pharynx (pp. 38-40) and shown in plates 2 

 and 6. 



Suprarenal gland. The suprarenal glands (Crl.s.-r.) are some- 

 what oval bodies of considerable size, developing in the ventral 

 region of the dorsal body wall between the Wolffian body and the 

 dorsal aorta. Their cephalic extremities lie at the level of the 

 ninth thoracic nerves, i.e., a short distance cephalad of the 

 caudal extension of the pleural cavities, of which they form, in 

 part, the caudo-lateral wall. Their caudal extremities lie on a 

 level with the twelfth thoracic nerves, i.e., slightly beyond the 

 cephalic extremity of the Wolffian body. 



