EXAMINATION OF CYSTICEECOID STAGES 157 



glottide, the testes being placed tlorsally, and the ovary and yolk-gland 

 ventrally, while between them lies the uterus, completely developed in 

 ripe segments only. The eggs are large and bullate, or polyhedral as 

 the result of mutual pressure, and the embryonal covering or pyriform 

 apparatus is prolonged into two branching horns. 1 



The life-history of the Anoplocephales of the horse is entirely 

 unknown, and this applies also to those of ruminants, of which a 

 large number are known to us. In spite of the researches of 

 Blanchard, Moniez, Perroncito, Kailliet, Stiles and Hassall, and 

 Cholodkowsky, our knowledge of the subject is still very limited 

 indeed. The species of Anoplocephalines which occur in ruminants 

 in Germany are : Moniesia expansa (Rud.), M. denticulata (Rud.), 

 and a variety which was at first called Tcenia ovilla, Riv., but was 

 afterwards renamed T. giardi, Mon., and is provisionally included in 

 the genus Thysanosoma, Dies. The two Moniezise (of which M. den- 

 ticulata usually occurs in cattle, while M. expansa is more frequent 

 in sheep) are, like all Anoplocephalines, devoid of both rostellum and 

 hooks. Each of the short, broad proglottides is furnished with a 

 genital pore at each marginal edge, which communicates with the 

 cirrhus-pouch and vas deferens or vagina. There are also two uteri, 

 two shell-glands, two ovaries, and two yolk-glands. The latter are 

 situated near the lateral margins, internally of the excretory canals, 

 while the numerous small testes (seen in mature segments only) 

 are distributed among the female organs, and do not, as a rule, 

 present a bilateral arrangement. The shape of the embryonal sac is 

 also very similar ; in both species it is drawn out into two long, 

 unbranched horns, which, in M. expansa, are 4 to 5 metres in length, 

 while in M. denticulata they attain a length of 40 cm. The species 

 are distinguished from one another by the length of these horns, the 

 rate at which the proglottides develop, and the occurrence of inter- 

 proglottidal glands. The latter are single-celled glands, which form at 

 the posterior margin of the segment, and frequently occur singly. In 

 M. expansa, however, they take the form of sacs, arranged in linear 

 series and communicating with the body-covering (fig. 79). 



Tcenia giardi, Mon., may grow to a length of 2 metres or more and 

 is usually furnished with alternating genital openings, though in some 

 segments these are duplicated. The greater number of segments 

 possess a single genital apparatus, placed internally to the excretory 

 canals, but in some segments this may also be duplicated. The 



1 Cf. Z. Kahane, " Anat. v. Taenia perfoliata " (Z. f. iviss. ZooL, vol. xxxiv, 1880, 

 pp. 174-254; F. Zschokke, "Eech. sur la struct, anat. et hist. d. Cestodes," Geneve, 

 1888; A. Scheibel, " Der Bau der Tsenia magna Abbild." (T.plicata, Zed.), in.-Diss. 

 (Giessen), 1895. 



