it is generally understood that the ova of the Seleroleptidota can effectually resist the action of ice and frost. As to the limited powers of resistance to heat possessed by Cysticcrei we are now well informed, but we can do little more in this place than refer to Professor Perroncito's experiments and to the enquiries of Lewis, Tommasi, Pellizzari, Giacomini, myself, and others, as set forth in a series of articles published in the London Medical Record for 1874. Professor Pellizzari found that measles died at a temperature of 60° centigrade, (i.e., 140 Fahr.) According to Lewis, exposure of the parasites for five minutes to the same degree of heat, or even to 135° Fahr., renders the life of these parasites absolutely extinct.
21.—Dothriocephalus latus, Bremser.
Synonymy.—Tænia lata, Luin; T. grisea, Pallas; Dibothrium latum, Diesing.
Intermediate Host.—The higher larvæ are supposed to reside in fishes, especially salmon and trout. According to Dr. Foek, of
Utrecht, the bleak (which is much eaten by Jews in Holland, who suffer from this tapeworm) is probably the intermediate bearer.
Larva.—Scolex unknown; Proscolex, or six-hooked embryo, furnished with long end closely-set cilia.
Remarks.—This worm is abundant in Switzerland, Russia, Sweden, and the north-east of Germany. It occasionally occurs in Ireland, but very rarely in England.
Experiments—All attempts to rear this worm have failed, although Dr. Knoch, of St. Petersburg, supposed he had succeeded by the administration of the eggs to dogs.
Literature—Leuckart (1. e.); Heller (l. c.}; Knock, Die Naturgeschichte des breiten Bandwurms, 1862; Sömmer and Lendois, Beiträge zur Anat., &c., in Sieb. and Köll. Zeitschrift, 1872; Bötcher, in Virchow's Arehiv, 1564.
22.—Bothriocephalus cordatus, Leuckart.
Syn.—T. vulgaris, Linn., Pallas.
Larva.—Unknown.
Int. Host.—Probably marine fishes.
Remarks.—This species is about a foot in length and is very abundant in the dogs of North Greenland. It occasionally infests man. The head is somewhat heart-shaped, and set on to the strobile without any neck or narrow segmentation intervening.
Lit.—Leuckart, Die mensch. Par., Bd. I., s. 438, 1863.
23.—Bothriocephalus cristatus, Davaine.
Syn.—None.
Larva.—Unknown.
Remarks.—This species is of moderate length, (8ft. to 10ft.,) and comparatively narrow. It is distinguished by the presence of a
crest-like vostellum. It has twice been found in France. The Westminster Hospital Museum contains some tapeworms probably referable to this species.
Lit.—Davaine, "Les Cestoides," Dictionnaire Eneyclopédique des Sciences Médicales}, (p. 589,} 1874.
Although the last-named species closes the list of human tapeworms, properly so called, yet no record of the Cestoies of man can be considered