Possible Clues:

• Coward's cry expressing pain
• Cowardly to act thus when in pain!
• Just a shade cowardly to cry out like this
• Yolk of egg
• Chicken or canary
• Telephone reference book
• So to cry out , it seems, is just a shade cowardly
• Lines round inside tree show sign of age
• See 15
• So cowardly to be calling Pa in like this, perhaps