P. parvamensis and the Hydropore

The 10 day old P. parvamesis larva has developed a hydropore, seen on the right of the photo. The hydropore, a small tubule, allows for preliminary gas and waste exchange to the hydrocoel.
The P. parvamensis larvae at this stage have a well developed gut, and in the photo, the mouth, esophagus, stomach and anus can be seen. The ciliary band (not labeled) is primarily around the mouth, to transport algae into gut.