6i6 



CESTOIDEA 



measured, on an average, 28-6 by 8-5 millimetres, but ranged from 

 21 by 6 millimetres to 32 by 29 millimetres in size. The central 

 uterine axis has twenty- two to twenty-four ramified lateral branches, 

 and one terminal branch with four to five ramifications. The genital 

 pore is prominent, and lies behind the middle of the segment. Eggs 

 measure on an average 38 by 3')-4 ^. 



Leiper considers that these large segments are relaxed Tcsnia saginata. 



Life-Cycle. — Nothing is known at present about the life-history. 



Echinocoeeus Rudolphi, 1801. 

 Synonym. — A cephalocy stis 'Lduenviec, id>o^. 



Species. — Echinocoeeus granulosus Batsch, 1786; E. muUilociilaris Huber 

 1896. 



Echinocoeeus granulosus Batsch, 1786. 

 Synonyms. — Tcenia echinococcvis Zeder, 1803, Siebold, 1853; T. nana van 

 Beneden, 1861, nec Siebold, 1853; Echinococcifer echinocoeeus Weinland, 1861. 



Hydatid disease appears to have 

 been known since the days of Hippo- 

 crates. In 1684 Redi suggested 

 that the cysts were animal in origin, 

 and in 1760-67 Pallas clearly showed 

 their relationship to tapeworms 

 {Tcsnia hydatigena). 



It appears doubtful whether there 

 are two species of worms associated 

 with hydatid disease, but the ap- 

 pearance of the larvae and the 

 geographical distribution tend to 

 separate the genus into two species. 



Echinocoeeus granulosus causes 

 the cystic form of hydatid disease, 

 which is found most markedly in 

 Iceland and Australia, but also 

 exists all over Europe, and is known 

 in New Zealand. It is rare in India, 

 and the only case we have seen in 

 Ceylon came from South Africa, 

 Fig. 254.— Cyst of Echinocoeeus where it occurs; but Begbie has 

 granulosus (Batsch, 1786). recently described another case m 



* ^ ' ' Ceylon. It is known m the Philip- 



(From a photomicrograph by J. J. Bell.) pine Islands, and is not uncommon 



in Egypt and Algeria, and we have 

 seen it in the Sudan. The mature worm, which is very small, lives in the 

 small bowel of the dog, the jackal, and the wolf in large numbers, while the 

 cysticercus is found in man, sheep, ox, and pig. 



Morphology. — It is very small, only 2-5 to 5 to 6 millimetres in length, and 

 is composed only of a scolex and three to four segments. The scolex has four 

 suckers and a rostellum armed with a double row of twenty-eight to fifty hooks, 

 which vary in size, the larger being 40 to 45 jji in length, and the smaller 30 to 

 38 in length. The genital pores alternate. 



The testes are numerous, the vas deferens spirally coiled, the vitellogene 

 gland double, the shell round. The mature uterus has only lateral pro- 

 tuberances, no true branches, and the eggs may form heaps. 

 The egg is globular, 30 to 36 jju in diameter. 



Life-Cycle. — The dog infects man with the onchospheres, usually directly 

 when being petted. Infection may, however, be brought about by contami- 

 nated food. 



On arrival in the stomach, the onchosphere escapes from its embryophore 



