Siebold classified the hookworm as belonging to the Strongyloidae (pp. 220-21).

Vol. 2 was published in 1846; Vol. 1 in 1848. Digital facsimiles of both vols. from Biodiversity Heritage Library at this link. Siebold was the author of  Vol. 1, on invertebrates; he introduced the taxa Arthropoda and Rhizopoda, and defined the taxon Protozoa specifically for single-celled organisms. Vol. 1 was translated into English and edited with notes and additions by Waldo I. Burnet as Comparative anatomy (London: Trubner & Co.; Boston: Gould and Lincoln, 1854). Digital facsimile of the English translation from Google Books at this link.

Siebold succeeded in infecting dogs with Taenia echinococcus. Translation by T. H. Huxley Sydenham Society London, 1857.