As I have remarked in a former comment on this singular case, one can have no difficulty in arriving at the conclusion that these parasites were obtained from the girl’s swallowing trematode larvæ, either in their free or in their encysted condition. Leuckart says it was not possible to ascertain whether the parasites had any connection with the gall-stones, or whether the two maladies, so to speak, were independent of each other; yet this question might possibly have been solved if the calculi had been broken up in order to ascertain their structure. It is just possible that dead distomes may have formed their nuclei, and if so, the circumstance would, of course, point to the worms as the original source of the malady. So far as I am aware, the actual transformations undergone by the larvæ of _Distoma lanceolatum_ have not been observed. The _Planorbis marginatus_ has been confidently referred to as the intermediate bearer of the cercariæ of the common fluke, and Leuckart supposes that the same mollusk harbours the larvæ of this species. The ciliated embryos carry a boring spine or tooth, and it is most probable that the higher larvæ are similarly armed. BIBLIOGRAPHY (No. 4).--_Kichner_ (see _Leuckart_), quoted above.--_Cobbold_, ‘Entozoa’ (p. 187).--The case by Bucholz (reported as one of _Fasciola hepatica_) is given by _Jördens_ in his work (quoted by Diesing and Leuckart) ‘Entomologie und Helminthologie des menschlichen Körpers,’ (s. 64, tab. vii, fig. 14), 1802.--_Chabert’s_ French case is quoted by _Rudolphi_ in his ‘Entozoorum sive vermium,’ &c. (_loc. cit._, Bibl. No. 1), p. 326, 1808. _Distoma crassum_, Busk.--This large species was originally discovered by Prof. Busk in the duodenum of a Lascar who died at the Seamen’s Hospital, 1843. It, however, remained undescribed until 1859, when, with the discoverer’s approval, I gave some account of it to the Linnean Society.