Figure 2 in REVIEW Vertebrate origins are informed by larval lampreys (ammocoetes): a response to Miyashita et al., 2021

Figure 2. Shared pharyngeal structures that are central to filter feeding in both ammocoetes and amphioxus, drawn in a composite pharynx. Lateral view with rostral to the right. These feeding structures are dominated by ciliary tracts and an endostyle gland. Tunicates largely show this same pattern. The ammocoete endostyle is more complex than the simple troughs present in amphioxus and tunicates, as drawn at bottom. The directions in which cilia move the food-laden mucus, as indicated by arrows, are the same in all three taxa. Note that the lamprey gill-seam tracts are located laterally, but they initially develop medially – in the same place as the branchial-bar tracts in amphioxus. After figure 1 in Mallatt (1984a), figure 1F in Mallatt (2009) and figure 1 in Barrington & Sage (1972).