FIG. 4.—_A_, _Peripatus novæ zealandiæ_.—After Sedgwick, from Lang. _B_, _Peripatus capensis_, side view, enlarged about twice the natural size.—After Moseley, from Balfour. _C_, Anatomy of _Peripatus capensis_. The enteric canal behind the pharynx has been removed. _g_, brain; _a_, antenna; _op_, oral or slime papillæ; _sd_, slime gland; _sr_, slime reservoir, which at the same time acts as a duct to the gland; _so_{4}_, _so_{5}_, _so_{6}_, _so_{9}_, nephridia of the 4th, 5th, 6th, and 9th pairs of limbs; _cd_, elongated coxal gland of the last pair of feet; _go_, genital aperture; _an_, anus; _ph_, pharynx; _n_, longitudinal trunk of the nervous system.—After Balfour, from Lang. _D_, Portion of the body of _Peripatus capensis_ opened to show the scattered tufts of tracheæ (_tr_); _v_, _v_, ventral nerve cords.—After Moseley. ] The genital glands and ducts are paired, but it is to be observed that the outlets are single and situated at the end of the body. In the male the ejaculatory duct is single; in its base a spermatophore is formed. It will be seen, then, that Peripatus is not only a composite type, and a connecting link between worms and tracheate arthropods, but that it may reasonably be regarded, if not itself the ancestor, as resembling the probable progenitor of myriopods and insects, though of course there is a very wide gap between Peripatus and the other antennate, air-breathing Arthropoda. [Illustration: FIG. 4.—_E_, _Peripatus edwardsii_, head from the under side: _a_, base of antenna; _op_, oral papilla; the figure also shows the papillæ around the mouth, and the four jaws.—After Balfour, from Lang. _F_, Anterior end of _Peripatus capensis_, ventral side, laid open: _a_, antenna; _z_, tongue; _k_, jaw; _sd_, salivary gland; _gs_, union of the two salivary glands; _ph_, pharynx; _œ_, œsophagus; _l_, lip papillæ around the mouth; _op_, oral or slime papilla; _sld_, duct or reservoir of the slime gland.—After Balfour, from Lang. ] =Relation of Myriopods to Insects.=—The Myriopoda are the nearest allies of the insects. They have a distinct head, with one pair of antennæ. The eyes are simple, with the exception of a single genus (Cermatia), in which they are aggregated or compound. The trunk or body behind the head is, as a rule, long and slender, and composed of a large but variable number of segments, of equal size and shape, bearing jointed legs, which invariably end in a single claw.