FIGURE 12. Spionid internal anatomy. A in Spionidae (Annelida) from shallow waters around the British Islands: an identification guide for the NMBAQC Scheme with an overview of spionid morphology and biology

FIGURE 12. Spionid internal anatomy. A, Spiophanes duplex, 13-segment anterior end of 23-segment juvenile, large glandular organs with long chaetae in segments 5–7, small glandular organs with short chaetae in segments 8–13, and gizzard-like structure (muscularized posterior part of oesophagus) in segments 10–11. B, Laonice petersenae, anterior end, ventral view, dark green excretory metanephridia from segment 4 and interneuropodial lateral pouches from segment 5. C, Prionospio heterobranchia, segments 6–9, dorsal view, main dorsal blood vessel with red blood and soft cylindrical heart body inside. D, Prionospio heterobranchia, middle part of pinnate branchia, arrangement of pinnules. E, Dipolydora quadrilobata, neuropodium of segment 8, glandular pouch composed by group of glandular cells covered by common envelop. bb—ventral buccal bulb; ch—chaeta inside glandular organ; dv—main dorsal blood vessel; gc—secretory cell of glandular pouch; gi— gizzard-like structure; gl—neuropodial glandular organ; gp—glandular pouch; hb—heart body; hh—hooded hook; lp—lateral interneuropodial pouch; mg—middle gut; ne—nephridium; oe—oesophagus; pi—branchial pinnule; s5–s13—segments 5–13. Scales: A, C–E—50 µm. B—500 µm.