The thick external wall is called the tunic and the inside layer is pierced by gill slits which circulate water. Nutrients are captured and brought into the stomach by the endostyle, which is a mucus secreting structure above the slit layer. One day and two day old ascidian eggs. If the substrate is adequate, the animal attaches itself and metamorphosis begins. After ten days the general appearance does not change and I have released specimens.
Internal organisation is similar to ascidians, with a tunic and gill slits inside.
But the tunic material is less transparent because it contains colored inclusions and only the input siphon can be seen clearly. Internally we can sometimes observe larvae which are released into the water and swim away to create a new colony. I have put a colony into a jar and a day later I have found two swimming larvae. With care, I have aspirated one with a pipette to take the picture below. You can see the tunic has protrusions which are used to fix itself to objects.