302 Veterinary Medicine. 



CcEnurus Serialis, the larva or scolex of the tania serialis, is 

 found in the connective tissue of various internal organs, includ- 

 ing the spinal canal of the rabbit. It may grow to the size of a 

 hen's egg, and contains lOO or 200 heads of the taenia in a single 

 sac. 



Taenia Marginata (Batsch). This inhabits the small intestine 

 of the dog, and is less common than taenia serrata as the hosts of 

 the scolex (cysticercus tenuicollis) , the ruminants, are le.ss fre- 

 quently devoured raw by the dog than are rabbits. Dogs kept 

 about slaughter houses are especially liable to suffer. 



The head is as narrow as the neck, or nearly so, and for some 

 distance the segments are marked only by transverse striae, yet 

 the mature caudal segments are twice as long as they are wide 

 (7 mm. by 15 mm.). The probo.scis is furnished with a double 

 row of hooks (130 ft and 200 /a), 30 to 44 in number, each handle 

 being curved in a direction contrary to the blade, and the guard 

 undivided. The genital pore marginal and slightly projecting ; 

 the oviducts divided in 12 or 16 branches ; the ovum round (33 /*). 



Cysticercus 'Vs.i\\3\zo'ViS& narrow-necked cysticercus, the larva 

 orscolex of taenia marginata, is found very frequently in the peri- 

 toneum of the domestic ruminants, and less so in the pig, or in 

 the pleura of ruminants. The cyst is elliptical, and may be i to 

 i^ inch in diameter. At the free end is the orifice through 

 which the scolex is invaginated, and if the whole is placed in milk- 

 warm water the head may be seen to rise and fall in the sac, 

 whence the name of diving bladder worm. If a lamb is fed some 

 ripe segments of the taenia marginata, it may die in 6 days with 

 the liver studded throughout its substance with little blood clots 

 each containing one or more of the transparent hooked embryo or 

 proscolex. By the loth daj^ some may be found in the peritoneum 

 and by the 25th day these may be in certain cases i cm. long. In 

 40 days they have been found 2]/^, cm. long and with well de- 

 veloped head. In 250 days they have attained their full size as 

 larvae. 



Pathogenesis. As taken in casually, one or two ova at a time, 

 this para.site has never been known to prove appreciably injurious 

 to ruminants. It is only when one or more ripe proglottides have 

 been administered or swallowed accidentally that a serious lesion 

 such as hepatitis or peritonitis has ensued. 



