THE WOLFFIAN AND JIULLEEIAN DUCTS. 



195 



nection with the hi nder end of the Wolffian duct, close to th e 

 cloaca, it attams a" large size in the male frog, b ut is absent or 

 rudimentary in the female. 



Fig. 88. — Transverse section through the anterior part of the body of a Tailed 

 Frog during the metamorphosis {of. Fig. 86). The section passes through 

 the second spinal nerve on the right side, and on the left side immediately 

 in front of this nerve, x 14. 



A, aorta. AP, pulmonary artery. CH, notocliord. CO, coracoid portion of 

 slioiUder girdle. FN", neural arch of vertebra. FT, transverse process of third vertebra. 

 G-C, glenoid cavity of shoulder gii-dle. G-M, glomerulus. HU, head of humerus. KS, 

 third or posterior nephrostome of head kidney. LGr, lung. LY, subcutaneous lymph 

 space. lie, spinal canal. WD, dorsal root of second spinal nerve. WU", dorsal and 

 ventral branches of second spinal nerve. W"S, spinal cord. ITV", ventral root of second 

 spinal nerve. WY", sympathetic nerve ganglion. RS, sinus venosus. SO, scapular 

 portion of shoulder girdle. SS, suprarscapular portion of shoulder girdle. TO, 

 cesophagus. VP, pulmonary vein. 



6. T he MuUerian Ducts. 



The Miillerian ducts form the oviducts of the female frog ; 

 they are present in the male as well, but are of very small size, 

 and apparently of no functional importance. The early stages in 

 the development of the Miillerian ducts are difficult to investi- 

 gate, and have not yet been determined with absolute certainty ; 



o 2 



