Читать книгу A Text-book of Entomology онлайн

15 страница из 232

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.

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.