other cestodes, is free at the commencement and the end of its life: at the beginning, in order to penetrate into its host; at the end, to scatter its eggs.
Messrs. Sommer and Landois published, in 1872, an anatomical description of the sexual organs of the Bothriocephalus latus, of such completeness, that it will be long before any one will again take up this subject, which had so much occupied helminthologists ever since the celebrated work of Eschricht. This memoir is illustrated by superb engravings, which represent these organs under every aspect. Dr. Böttcher, of Dorpat, found in the small intestine of a woman, who died of peritonitis, at least a hundred Bothriocephali. They were but slightly developed, though there were some in a sexual state.
The largest tænia, though not the longest, is the Tænia magna, from the Rhinoceros, described by Marie; it is, no doubt, the same to which the name of gigantea was given by Peters. The learned director of the Museum of Berlin gave me a fine specimen of it eighteen years ago. The generic name of Plagiotænia has been proposed for this worm.
Almost all birds nourish large and beautiful tæniæ, but they must be studied immediately after the death of their host. They often change their form entirely at the end of a few hours.
Woodcocks and snipes always have their intestines stuffed full of tæniæ and the eggs of these worms. Every bird contains them by thousands. Fortunately we cannot be infested with the tænia of the snipe and the woodcock.
[Fig. 61] represents the scolex of the Tænia variabilis
of the snipe, and [Fig. 62], by its side, shows the crown of hooks more highly magnified. We have made these drawings from worms collected from snipes some instants after their death. We close this chapter on the cestodes with the plate ([Fig. 63]) of a Tetrarhynchus which is usually found in the plaice. The perfect tetrarhynchi, that is to say, those that are adult and sexual, inhabit the intestines of voracious fishes, especially of the squalidæ.
Fig. 61.—Tænia variabilis from the snipe.