Henry Hallett Dale

Scorpion Henry Hallett Dale

Asterias Henry Hallett Dale

Insect structure Henry Hallett Dale

Physalia Henry Hallett Dale

Sepia officinalis Henry Hallett Dale

Periplaneta orientalis Henry Hallett Dale

Gammarus fluviatilis Henry Hallett Dale

Ascaris lumbricoides Henry Hallett Dale

Antedon Henry Hallett Dale

Holathuria tubulosa Henry Hallett Dale

Sepia officinalis Henry Hallett Dale

Sepia officinalis Henry Hallett Dale

Caterpillar and pupa Henry Hallett Dale

Chaetognatha Henry Hallett Dale