PATHOLOGIC OVA, ALBINO RAT Yas 
p. ect 
pr.emb. ent —| 
ect n. 
Fig. 8 Egg-cylinder of albino rat showing retarded development of ecto- 
dermal node and of the formation of the antimesometrial portion of the pro- 
amniotic cavity. > 200. Rat No. 94, 8 days after the beginning of insemina- 
tion. ect.pl., ectoplacental cone or Triiger; v.ent., visceral entoderm; met.pr., 
mesometrial portion of the proamniotic cavity; p.ect., parietal or transitory 
ectoderm; pr.emb.ent., primary embryonic entoderm; ect.n., ectodermal node; 
a.met.pr., 1mperfectly developed antimesometrial portion of proamniotic cavity; 
ex.ect., extraembryonic ectoderm. 
ectoderm, in structure and relation to decidual crypt, are to be 
regarded as of normal development. The visceral entoderm, 
surrounding the extraembryonic ectodermal portion of the egg- 
cylinder, is of normal structure, showing the three zones evidenc- 
