50 M. R. CURTIS AND RAYMOND PEARL 



An examination of the bird's egg record shows that she started 

 her year with two 2-egg clutches, and a separate egg in October, 

 a record not unUke that of many birds which are good layers. 

 There were only three eggs recorded after October 26 ; these were 

 scattered; their dates of laying were December 18, February 4, 

 and February 15. However, in November the bird began to 

 go on the nest daily and the nesting records follow rhythms 

 very similar to the rhythm of laying of a good egg-producer. The 

 three irregular eggs recorded after October were in rhythms of 

 nesting and ma}^ have been (and probab y were) errors due to 

 an egg having been left in the nest the last time it was used, or 

 to the attendant accidentally recording an egg instead of a nest- 

 ing record. An accurate determination of the time, or of the 

 cause, of the rupture of the oviduct is impossible. It seems 

 clear, however, that at the time it occurred there must have been 

 a completed egg in the lower end of the duct. This egg was 

 evidently carried up the duct and through the rupture into the 

 body cavity by an antiperistaltic movement of the duct, which 

 accompanied or almost immediately followed the rupture. This 

 egg was evidently resorbed through the abdominal peritoneum, 

 leaving the collapsed membrane found at autopsy. The nesting 

 rhythm of the bird; the egg and serum mixture containing the 

 short tubes of egg membrane found in the body cavity; and the 

 normal naked egg in the lower part of the albumen-secreting 

 region; all make it seem certain that after the rupture of the 

 duct the sex organs passed through their normal cycles and 

 that the eggs were formed in a normal manner, so far as the 

 rupture of the duct allowed. After passing through the rup- 

 ture they were absorbed directly through the general peritoneal 

 surface. 



Bird No. 81 had the two lips of the funnel tightly fused. In 

 order to test this observation the duct was filled with water 

 and the union of the edges of the funnel lips proved watertight 

 except at one point at the lower angle of the mouth of the ovi- 

 duct; through this the water slowly oozed; it was impossible 

 for a yolk to enter the duct. Both ovary and oviduct were 

 in laying condition. There were small lumps of absorbing 



