This tapeworm is the longest. It measures from five to eight metres. The head is elongated, of almond shape, being about 2.5 mm. in length (Fig. 47). It has two lengthy big grooves on its flat surface (Fig. 48). The neck is narrow, about 2 cm. long. The body is thin and flat like a ribbon, excepting the central part of the segments which project somewhat outward. The genital openings are on the flat surface in the middle, the female very close to the male. The uterus has a special opening and four to six visible uterine convolutions on each side, which look almost like a rosette. The eggs are oval, round, with a thin membrane and a lid (Fig. 49). They measure 0.07 mm. in length and 0.04 in width.

The Uterus and its Branches in a Segment of Taenia Saginata

Fig. 46. - The Uterus and its Branches in a Segment of Taenia Saginata. Enlarged 3 diameters. (Huber.)

The measle of bothriocephalus latus occurs principally in fish, especially in pike, turbot, perch, and trout.

The taenia lata lives in the small intestine of man, but is also, though rarely, found in dogs. In the northeastern part of Europe, Holland, Switzerland, and Japan this tapeworm is very prevalent. In America it occurs but infrequently. As stated above, among the symptoms produced by bothriocephalus anaemia is often observed.

Aside from the three tapeworms just described there exist a few more varieties which are only rarely met in human beings. They are:

(1) Taenia Nana

This is the smallest tapeworm found in man. It measures 10 to 15 mm. in length and may have one hundred and ninety segments. The head has four sucking - discs, a rostellum, twenty - four to twenty-eight hooklets in a single row. The proglottides are short and broad; the genital openings are on one side. This tapeworm has been observed principally in Egypt and Italy in children. It usually occurs in large numbers in the small intestine, from forty to even five thousand. The symptoms produced by this tapeworm are mostly nervous disturbances, fainting spells, occasionally even epilepsy.

(2) Taenia Cucumerina

This small cucumber-shaped tapeworm occurs frequently in the intestine of the dog, but has also been found, although rarely, in small children. The tapeworm is 10 to 40 cm.

Bothriocephalus Latus Natural size

Fig. 47. - Bothriocephalus Latus Natural size. (Leuckart.) long and about 3 mm. wide. The measle of this taenia inhabits the flea.

(3) Taenia Flavo-Punctata Or Toenia Diminuta

This parasite is 2 to 6 cm. long and 3.5 mm. wide. Its head is very small, club-shaped, and provided with sucking-discs. The measle infests the caterpillar and cocoon of asopia famialis and in the coleoptera axispinosa. This tapeworm has been observed in man only a few times.

Head of Bothriocephalus Latus. Magnified

Fig. 48.

Eggs of Bothriocephalus. (Krabbe.)

Fig. 49.

Fig. 48. - Head of Bothriocephalus Latus. Magnified. (Heller.) Fig. 49. - Eggs of Bothriocephalus. (Krabbe.)