312 FLAT WORMS 



From the germinal layer arise the brood capsules and the scolices. In these brood 

 capsules we have the cellular layer external just the reverse of the mother cyst. 

 Scolices may develop either on the outside or inside of these brood capsules. It is 

 interesting to note that one onchosphere may develop hundreds of scolices. From 

 the parenchymatous layer of the mother cyst, daughter cysts are formed; these have 

 an external stratified layer and an internal parenchymatous one; within them a vary- 

 ing number of scolices may develop. From these daughter cysts, granddaughter 

 cysts may arise all within the mother cyst and hence are termed endogenous. 



At times the daughter cysts work their way external to the mother cyst and pro- 

 ceed to develop in a manner similar to the endogenous formation. The exogenous 

 development is rare in man, but common in hogs. Hydatids containing no scolices 

 are called sterile. These cysts may be as large as a child's head, but are usually 

 smaller. The fluid of these cysts contains about i% of NaCl, also a trace of sugar; 

 in addition there is a toxin which produces urticaria and acts as a cardiac depressant. 

 If any quantity should escape into the peritoneal cavity at operation, it may cause 

 death. Hydatids develop very slowly, and the duration of the disease is usually 

 from two to eight years. 



Echinococcus multilocularis is possibly due to a species different from T. echino- 

 coccus. In this we have a honeycomb arrangement with cavities filled with a gela- 

 tinous material. The majority of these cysts are without scolices. This form of 

 hydatid is very fatal. 



Sparganum mansoni (Bothriocephalus liguloides). This is a larval bothrio- 

 cephalid which is about 5 to 10 inches long and has been reported 10 times in Japan. 

 It has been found in various parts of the body, as in pleural cavity, tissues about 

 kidney, and in abscess of the thigh. They have been found in the urethra and under 

 the conjunctiva. They resemble ribbon-like strings of fat. 



Sparganum prolifer (Plerocercoides prolifer). This has been reported from 

 Japan as a larval form in the subcutaneous tissue. Stiles has found these larval 

 forms in skin lesions in Florida. They show themselves as bizarre grub-like forms. 

 They reproduce by budding. 



