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Fig. 1. Nervous system of Horse-leech. The first incrassated portion of the nervous cord represents the Drain, the rest ganglionic enlargements. Fig. 2. Plan of ventral blood-vessel according to Dr. Rawlins Johnston. The outer black line represents the ventral vessel; the inner line the nervous cord enclosed in it Fig. 3. Head of the horse-leech, showing the arrangement of the eyes. Fig. 4 Nervous ganglion magnified 200 diameters. Fig. 5. Portion of integument of abdomen, showing four openings of the mucous vesicles. Fig. 6. Magnified view of Respiratory Apparatus, a. lateral vessels, b. loop shaped gland, c. mucous vesicle. Fig. 7. Eye with choroid coat entire. Fig. 8. Eye with choroid coat partly removed. Fig. 9. Respiratory system of the Horse-leech.

venous system of the horse-leech is represented by two vessels with their communicating branches, one situated on the dorsal, the other on the ventral aspect of the body. They are both much smaller than the lateral vessels which have been previously described; and