DIBOTHRIOCEPHALIDyE 245 



The African tapeworm, Tcenia africana, is a species found in 

 German East Africa. It is about four feet in length with no 

 hooks on the scolex (Fig. 87E) and with an unusual fanlike ar- 

 rangement of the uterus in the ripe proglottids (Fig. 84G). Von 

 Linstow, who described the worm, suggests that the zebu may 

 be the intermediate host since its flesh is eaten raw by the 

 natives. 



A medium-sized tapeworm, Tcenia philippina, reaching a 

 length of about three feet, has been found among prisoners at 

 Manila. It very much resembles the African tapeworm but has 

 smaller proglottids. Other species have been described from 

 various parts of the world, especially southern Asiatic Russia, 

 but they are of such rare occurrence, some having been found 

 only once, that they need no description here. 



Two specimens of the species Tcenia confusa, of which the 

 scolex is unknown and which consists of from 700 to 800 proglot- 

 tids, were found by Ward in Nebraska many years ago, but so 

 far as the author is aware no specimens have been obtained since. 

 A ripe proglottid of this species is shown in Fig. 84D. 



Of the accidental tapeworms of man there should be mentioned 

 especially the dog tapeworm, Dipylidium caninum. This species 

 is abundant in dogs, and sometimes cats, in all parts of the 

 world. It is a species about a foot in length, with three or four 

 rows of hooks on the rostellum (Fig. 87F), and a double set of 

 reproductive organs in each proglottid (Fig. 84C). The larva, 

 a cysticercoid, occurs in lice and fleas. It is stated that the eggs 

 of this tapeworm cannot be sucked up by the dog-infesting fleas, 

 but that they are readily swallowed by flea larvse. The eggs hatch 

 in the intestine of the flea larvae, the embryos pass to the body 

 cavity and the cysticercoids remain through the metamorphosis 

 of the larvse to the adult fleas. Children who play with dogs 

 are occasionally infested by this worm, probably by accidentally 

 swallowing lice or fleas or by crushing them and then putting in- 

 fected fingers into the mouth. 



Family Dibothriocephalidae 



The tapeworms of this family, as remarked before, are charac- 

 terized by a flattened head with two slitlike suckers (Fig. 87C 

 and D). The larvse, which usually develop in fishes, are of the 



