Development of the so-called double-walled blood vessels of the thymus.
D000818:Animals; D001158:Arteries / Q000166:cytology; D001808:Blood Vessels / Q000166:cytology*; D002196:Capillaries / Q000166:cytology; D002415:Cats; D002417:Cattle; D004285:Dogs; D005260:Female; D005333:Fetus / Q000166:cytology; D006651:Histocytochemistry; D006801:Humans; D008722:Methods; D008853:Microscopy; D011247:Pregnancy; D051381:Rats; D013950:Thymus Gland / Q000098:blood supply* / Q000166:cytology / Q000254:growth & development; D014680:Veins / Q000166:cytology