5. _Campodea_ breathes by means of three stigmata in the anterior part of the body. The stigmata of _Scolopendrella_ are hard to see, and are not in the same position. 6. _Scolopendrella_ has twelve pairs of legs, and _Campodea_, like all Insects, has only three. I will now go on to an account of their anatomy. The body is small and slender, and is covered with a delicate shell or exoskeleton of chitin, which is so thin as to be almost transparent. The _antennae_ are long, and are composed of many joints of equal size. The _mouth parts_ consist of— 1. An upper lip. 2. A pair of mandibles. 3. A pair of maxillae. The segments are not all of equal size. Some are larger than others. The larger and smaller segments are arranged alternately, and the smaller do not bear legs. As before stated, there are twelve leg-bearing segments. At the end of the body there are two hook-like appendages which are pierced by a canal, through which is poured the secretion of a pair of glands. Near the sides of these appendages are a pair of sense organs, consisting of long hairs connected with nerves. {62}The digestive canal is a long straight tube passing through the length of the body. In the middle it is much enlarged, so as to form a stomach with a glandular coat. Posterior to the stomach the digestive tube receives the contents of two Malpighian tubes which act as kidneys. The tracheal system consists of a single pair of stigmata on the under surface of the head, and the tracheae connected with them. ORDER V. PAUROPODA. The Pauropoda, which form the fifth Order of Myriapods, are as yet very imperfectly known. _Pauropus_ was discovered by Sir John Lubbock, and its discovery was announced by him in 1866. He found this little Centipede in his kitchen garden among some Thysanura, and at first considered it as a larval form, but continued observation showed that it was a mature creature. He described it as a small, white, bustling, intelligent little creature about 1/25 inch in length. The antennae are very curious and highly characteristic of the Order. They resemble those of Crustacea rather than those of Myriapoda. Each antenna is composed in the following manner. First there is a shaft of four joints. From the fourth joint of this shaft spring two branches; one of these two branches is narrower than the other, and ends in a long thin bristle composed of a great number of joints. The other and broader branch bears two such bristles, and between them a small pear-shaped or globular body, the function of which is unknown.