The Bloodworm - cardiovascular systems

A multiscale approach reveals elaborate circulatory system and intermittent heartbeat in velvet worms (Onychophora)

Circulatory system of earthworm

Planaria Digestive System - Lesson

Annelida - Circulatory System

Annelida - Circulatory System

PDF) A Review of the “Open” and “Closed” Circulatory Systems: New Terminology for Complex Invertebrate Circulatory Systems in Light of Current Findings

Toxins, Free Full-Text

Feather Duster Worm - cardiovascular systems

PDF] A Review of the “Open” and “Closed” Circulatory Systems: New Terminology for Complex Invertebrate Circulatory Systems in Light of Current Findings

Brief Comparative Phylogeny

Chapter 2 – The Breath of Life in Insects and Humans – Insects & Human Affairs: Pests, Plagues, Pollinators and Poisons

Earthworm: Circulatory system, Blood vessels & their arrangement

Annelid - Respiratory, Segmented, Setae