176 EDWARD A. BOYDEN 
pass through three diverticula, the broad one (a), and two smaller 
ones (b and c, members of the terminal circlet of diverticula). 
The arrow indicates that the duct in sections higher up would 
reach as far as the point c. In subsequent stages the mesial 
wall of the duct would fuse with the cloacal diverticula forming 
WI 
SES 
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\ 
Fig. 6 | ; 
TEXT PLATE ILLUSTRATING ANOMALIES OF THE WOLFFIAN DUCT 
Fig.6 Chick, H.E.C. 2071 (section 661):2 days, 18 hours. X77. a, proximal 
complemental diverticulum; 6 and c, distal complemental diverticulum; arrow 
indicates extent of wolffian duct in other sections. Note thinning out of mesial 
wall of duct in preparation for fusion with cloaca. 
Fig.7 Duck, H.E.C. 2194 (section 680): 3 days, 21 hours. X 77. mes., 
mesenchyma interposed between distal and proximal attachments of duct. 
Fig.8 Chick, H.E.C.2073:2 days,2lhours. X77. x, plate formed by fusion 
of mesial wall of W. D. with complemental diverticula of cloaca; arrow shows 
where plate has been ruptured, through distal diverticulum. 2 
Fig.9 Chick, H.E.C.2072:2 days,22 hours. X77. Arrow shows where plate 
has been ruptured through proximal diverticulum. 
Fig. 10 Model of duck embryo, H.E.C. 2197: 4 days, 8 hours. X 40. all., 
allantois; an. pl., cloacal membrane; c.7., caudal intestine; cy., epithelial cysts of 
unknown origin; fen., fenestra; t. p., terminal portion of W. D.; ur-, primordium of 
ureter; W.D., wolffian duct. 
Fig. 11 Model of duck embryo, H.E.C. 2195: 4 days, 8 hours. X 40. div., 
aberrant complemental diverticulum. 
