164 



EDWARD MCCRADY, JR. 



XIII. THE THIRTEENTH DAY. Stages 34 and 35 



The first half of the thirteenth day 



Stage 34. External distinctive features. The abdominal, 

 epigastric and umbilical veins. The diaphragm. The peri- 

 neum. The oral shield. The palate. The mammary anlagen. 

 Connection between thoracic duct and jugular sacs. Mis- 

 cellaneous details. 



34 



Fig. 53 Photographs of 16179 (stage 34). A, ventral view showing oral 

 shield very clearly. Lateral view showing epitrichial growth over eyes, ears, 

 and sides of mouth. 



External distinctive features. Stage 34 is distinguished 

 i'rom stage 33 by the epitrichium, which covers the eyes, ears, 

 and the sides of the mouth; by the oral shield (fig. 53, A) ; by 

 the claws on the forefoot and the digital ridges on the hind- 

 limb paddle; by the absence of any external intestinal loop; 

 and by a noticeable elongation of the trunk. It is distinguished 

 from stage 35 by the well-developed oral shield; and by the 

 fact that the digital anlagen on the hindlimb are ridges, not 

 buds. 



