204 FLAT WORMS. 



drops into the lumen of the gut, and a new parasite is added to the 

 already existing number of parasites. This explains the heavy 

 infection. H. diminuta and H. lanceolata have also been reported 

 for man a few times. 



Dipylidium caninum. This is a common parasite of dogs and 

 cats. The larval stage is passed in lice and fleas. The cases of human 

 infection have been principally in children, probably from getting dog 

 lice or fleas in their mouths. The head has 4 suckers and a rostellum. 

 which has 3 or 4 rows of encircling hooklets. The segments have the 

 shape of melon seeds and have bilateral genital pores. 



Davainea madagascariensis. This tape-worm has been found in 

 Siam and Mauritius. It is about 10 inches long. The head has 4 

 suckers and a rostellum with 90 hooklets. The genital pores are 

 unilateral. The cockroach is supposed to be the intermediate host. 



DIBOTHRIOCEPHALID.E INFECTIONS. 



Dibothriocephalus latus. This is frequently termed the broad 

 Russian tape-worm. It has a small olive-shaped head with 2 deep 

 winding suctorial grooves on each side; it has neither rostellum nor 

 hooklets. The segments are quite broad, being about. 1/2 by 1/5 in. 

 At the end of the strobile they are more nearly square. The segments 

 are very numerous, 3000 or more. The fully developed worm is about 

 30 feet long. The uterus in each segment is rosette-shaped and the 

 genital pore is ventrally situated. The eggs of this species have an 

 operculum and a ciliated embryo. This ciliated embryo swims 

 around and either enters some fish, especially pike, directly or through 

 an as yet unknown intermediary. This parasite produces an intense 

 anaemia similar to pernicious anaemia. It is a frequent parasite in 

 Switzerland, Bavaria, Japan, Scandinavia and Russia. Recently 

 several cases have been reported from our Northwest, and some of the 

 fish of the waters of that region are said to be infected. The larva is a 

 plerocercoid and is about i inch long. It is said that salting, smoking 

 or other ordinary methods of preserving fish will not kill it. 



A tape-worm, Diplogonoporus grandis has been reported from 

 Japan. In this there are 2 complete sets of genital organs to each 

 segment. 



