Name: early pluteus larva stage
ECAO ID: 0000460
Definition: "The embryo is by now a fully formed pluteus larva. The mouth has opened and the digestive tract is becoming functional. On the ventral side, the mouth is surrounded anteriorly by an oral hood and posteriorly by two postoral arms. On the dorsal side, the apex has lengthened. The skeleton has indeed continued extending, expending the dorsoventral connecting rods, the body rods, and the ventral transverse rods as well as developing the anterolateral rods and the postoral rods. Within the larva, the tripartition of the digestive tract has further progressed. The cardiac sphincter is now fully formed in between the esophagus and the stomach, and the pyloric sphincter in between the stomach and the intestine and the anal sphincter at the level of the anus have also started forming. Around the esophagus, the coelomic pouch has further developed into two bilobed sacs (or pouches), one on each side of the digestive tract. Finally, within the apical pole domain, as well as within the ciliary band, differentiated neurons with their extended axons can also now be distinguished by immunostaining. In parallel, the apical tuft of long and immotile cilia remains discernable at the tip of the oral hood, while in parallel the ciliary band has further started growing a concentrated number of intermediate size motile cilia, which will be used by the larva to swim directionally."
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