48 
Subfamily DIPYLIDIINiE a Stiles, 1896. 
Subfamily diagnosis. — Txniidx (p. 24): Suckers unarmed. RosteHrum armed, 
rarely absent. Genital pores marginal (lateral), single or double and opposite. 
Genital organs of each segment in single or double series. Uterus usually dividing 
up into egg sacks, or entirely disappearing so that the eggs lie free in the parenchyma. 
Eggs with thin transparent shells, with or without appendages. Larval forms 
(cysticercoides) in arthropods or mollusks. Strobila in mammals, birds, and reptiles. 
Type genus. — Dipylidium Leuckart, 1863. 
Of the genera Dipylidium, Cotuynia , Oochoristica, Dancer ici, Monopylidium, Hymen o- 
lepis, Dilepis, Choanotxnia, Amcebotxnia, and Nemalotsenia , two groups ( Dipylidium 
and Ilymenolepis ) are represented among the parasites of man. 
KEY TO GENERA OF DIPYLIDIINVE FOUND IN MAN. 
Genital organs in double series; numerous testicles in each segment _ Dipylidium (p.48) 
Genital organs in single series; 3 testicles in each segment Hymenolepis (p. 51 ) 
Genus DIPYLIDIUM 6 Leuckart, 1863. 
Generic diagnosis. — Dipylidiinx: Rostellum retractile, armed with several rings 
of alternating rose-thorn hooklets, which usually have a discoidal base. Suckers 
unarmed. Genital pores double and opposite. Genital organs in double series. 
Testicles very numerous, in median held. Ovary bilobed. Yitellogene glands distal 
of ovary. Uterus at first representing a reticulum, in the meshes of which are situ- 
ated the testicles; later it breaks up into egg sacks inclosing one or several eggs. 
Eggs with double shell. Parasitic in mammals. 
Type species. — Dipylidium caninum (Linnaeus, 1758). 
« Synonyms. — Ilhynchotxnia Diesing, 1850a; Malacolepidoia Weinland, 1858a; Cys- 
toidese Leuckart, 1863; Cystoidei Leuckart, 1886; Cystoidotxnix Railliet, 1886; Microtsenix 
Claus, 1891; Dipylidirnv Railliet, 1896. 
& Synonyms. — Txnia ( Dipylidium ) Leuckart, 1863; A l:\pelmindias Weinland, 1858, 
not Zeder, 1800; Cryptocystis Yillot, 1882; Microtxnia Sedgwick, 1884. 
