CESTODES 515 



ova, the shells of which are radially striated, enclose the oncosphere which is 

 supplied with six booklets. 



Malformations are rarer than in the tenia saginata. I wish to mention 

 only the three-edged or prismatic tenia which is produced, not as was fre- 

 quently assumed from a twelve-hooked oncosphere, but by the coalescence of 

 two scolices with one-half of their dorsal surfaces, whereas the other two 

 halves remain free; it appears that the dorsal parts of the coalescent halves 

 are at the same time greatly retarded in growth. 



The asexual immature form is the cysticercus cellulosse, the finn of swine, 

 which is found principally in the pig, but also in other mammals. The mode 

 of infection of the pig and of man is well known. 



The cysticercus cellulosse occasionally also shows malformations. Such 

 are the cysticercus (tenia) acanthotrias Weinland and the cysticercus race- 

 mosus which is formed like a bunch of grapes and possesses many branches; 

 the latter is found in the brain and in the heart. This upsets (according to 

 the views of Eedon, Blanchard, Eaillet and Braun) the hypothesis of a special 

 genus of tenia (cysticercus) acanthotrias. 



The second variety, the tenia saginata, is more rounded and larger than 

 the tenia solium, and has the following characteristics : The head is larger, 

 the row of booklets and tlie rostellum are absent; the suctorial discs are 

 markedly developed. The proglottides are supplied with irregularly alter- 



FiG. 36. — Ova of Tenia Solium. Fig. 37. — Ova of Tenia Saginata. 



The enlargement is the same in Fig. 36 and Fig. 37. 



nating sexual papillae; they show a uterus with 20 to 30 or even more lateral 

 branches; the sexually mature members which are cast oS spontaneously are 

 frequently found without ova, because the latter have been discharged prema- 

 turely owing to a lesion of the uterus. The ova are similar to those of the tenia 

 solium (see illustrations). Malformations in the chain of links occur more 

 frequently than in the former variety. 



Cysticercus bovis, which is the young form of this parasite, is principally 

 found in cattle. Whereas the cysticercus cellulosse is sometimes found in the 

 organs of man, particularly in the brain and in the eye, generally through 

 autoinfection, only four cases have been reported in which the cysticercus 

 bovis has been found in man. It is probable, however, that these four cases 

 were not due to the cysticercus bovis at all, but to malformations of the 

 cysticercus cellulosae. 



Man is considered to be the only host of these two forms. DefEke suc- 

 ceeded recently, by feeding the cysticercus cellulosse to three dogs, in obtaining 

 in two of the dogs small specimens of tenia solium. The delicate specimens 

 gave the impression that they were in the process of expulsion. 



Tenia solium has for several decades become steadily rarer. This is evi- 



