1. The labral glands consist of a proximal and a distal group of gland-cells.
2. The proximal group consists on each side of about twenty cells. The cells possess large flat nuclei and their secretion collects as intercellular vaeuoles.
3. The distal glands which are in connexion with the proximal groups consist on each side of five cells--four gland-cells and a duct-cell. The anterior pair of gland-cells possess large spheroidal nuclei between which is an ill-defined reservoir of secretion. The posterior pair have cup-shaped nuclei between which is a very definite reservoir of secretion.
4. The duct-cell is in the form of a hollow tube, one end opening to the exterior near the tip of the labrum and the other end opening into the reservoir of secretion between the nuclei of the posterior pair of distal gland-cells. The duct-cells act as ducts for the whole of the labral glands, the secretion passing as vacuoles from cell to cell.
5. The duct-cell alters the reaction of the secretion before passing it to the exterior.
6. Food particles carried in the stream which is maintained by the trunk-limbs through the carapace are abstracted by the gnathobases of the second trunk-limbs.
7. There are ten setae on the gnathobase of the second trunk-limb, the anterior three of which are comb-like and brush the secretion of the labral glands on to the food particles as they collect between the maxillae.
8. The setae of the maxillae are directed anteriorly, and by their action pass the food on to the mandibles at the entrance, of the oesophagus.
9. The labral glands stain very markedly intra vitam with neutral red and Bismarck brown. There is no evidence that this effect is due to the staining of the preformed structures in the protoplasm.
10. Females stained intra vitam with neutral red. when removed to fresh water will lay red eggs from which young will hatch which are also stained. The stain disappears from these during growth.
11. Agar's experiments on the transmission of an abnormality produced by a certain food are criticized. This abnormality can bo produced by feeding Simocephalus vetulus with Chlamydomonas.
12. The secretion of the gland contains no mucin.