CESTODA. 



259 



no segmentation, but the generative organs are repeated. They live in the 

 body cavity of Teleosteans and become sexually mature in the intestine of 

 birds. L. simplicissima Rud., in the body cavity of fishes and in the intestine 

 of aquatic birds. L. tuba v. Sieb., in the intestine of the tench. 



Fam. 3. Tetrarhynchidae. Head with two or four suckers, and with four 

 protractile proboscises armed with hooks (Fig. 217) ; genital openings marginal. 

 The scolices live encysted in bony fishes, and the sexual worms in the intestine 

 of skates and rays. Tetrarhynchus Cuv., with four suckers ; Rhynchobothrium 

 Blainv., with two suckers. 



Fam. 4. Echinobothridae. With two suckers and two armed proboscises ; 

 genital openings marginal. Echinobothrium v. Ben. 



Fam. 5. Tetraphyllidae. Head with four very mobile suckers often armed 

 with hooks. Proglottides detached singly. Genital pores marginal. In the 

 intestines of Selachians. 



FIG. 216. Generative organs of a sexually mature proglottis of Bothriocephahis latus (after 

 Sommer and Landois) ; a, from the ventral surface ; 6, from the dorsal surface. Ov and v 

 ovary ; Ut uterus opening to the exterior independently of the vagina ; Sd shell-gland ; 

 Dst vitellarium (yolk -gland) ; Va vagina with opening; T testes ; Cb pouch of the cirrus; 

 Vd vas deferens. 



Sub-fam. 1. Phyllobothrinae. Suckers without hooks, more or less 

 stalked. Echeneibothrium v. Ben.; Phyllobothrium v. Ben., suckers sessile; 

 Anthobothrium v. Ben. 



Sub-fam. 2. Phyllacanthinae. Suckers armed, each with 2 or 4 hooks. 

 Acanthobothrium v. Ben. ; Calliobothrium v. Ben. ; Onchobothrium Blainv. 

 Fam. 6. Taeniadae. The armature of the head consists of four muscular 

 suckers, to which is frequently added a single or double circle of hooks on 

 the rostellum. The proglottides have a marginal sexual opening. The vagina 

 is usually long, and enlarged at the internal end to form a receptaculum seminis 

 (Fig. 201). The uterus is without a special opening to the exterior. The young 

 stages are Cysticerci or Cysticercoids, rarely quite without caudal vesicle. 

 Parasitic in warm and cold-blooded animals. 



Sub-fam. 1. Cystotaeniinae. Rostellum usually with double row of 



