Introduction to Animal Morphology. 169 



second day of freedom, and the body lengthens, and 

 shows transverse lines, deepening into joints. 



There are about 265 species, divided into seven families. 

 i. Taeniichv worms of many metameres ; head with four 

 suckers (Fig. 23, B); sex openings usually marginal. Gymno- 

 .Lt have no rostellum nor hooks, and inhabit herbivorous 

 Mammals, Man, Amphibians, and Teleostean fishes. G.medio- 

 canellata (Fig. 23, B), with a black ring round each sucker, 

 dichotomousuterinepouchesand oval eggs is a common human 

 parasite in this country, Siberia, Abyssinia, cScc., and some- 

 times is 1200 jointed. G. perfoliata and plicata occur in the 

 horse. G. dispar in frogs. G. pectinata in hares. Echino- 

 taenia has a rostellum and 1-4 circlets of hooks, and is para- 

 sitic in Carnivores and Omnivores, Man, &c. E. solium, the 

 common tape-worm of Western Europe, has two alternating 

 circlets, one of larger, one of shorter hooks, twenty-six in all, 

 each with a short process at its root, and often black hook 

 follicles; the uterine follicles are dendritic, and contain 

 spheroidal ova; its larval stage (Cysticercus cellulose) is the 

 ;site of measly pork. E. echinococcus, of the dog, rarely 

 in Man (Iceland), consists only of 3-4 nT'tameres, and has a 

 rostellum; its scolex is the hydatkl of the human liver 

 hinococcus hominis). E. crassiceps, of the fox, develops 

 fron. rcus longicollis of the field-mouse. E. elliptica, 



of the cat, once found in a child, has double sex-organs in 

 b pro-lottis. E. acanthotrias is only known in its scolex 

 a human parasite with three rows of hooks. K. 

 platycollifl is developed from the human C. turbinatus (Kobcr}. 

 ma, found in an Egyptian boy, has an oval rostellum 

 with one row of hooks. K. marginata, of the dog and wolf, 

 v in Man, develops from ('. tenuicollis of ruminants 

 "in<; ! punetala, named from the colour of the 



Ii- when lull, was oner found in Man. I-'., ser- 

 i (.'. pisilonnis of the han- : 1 



\ the rat and mouse. 



:rus, with a rostrllum ami tv of hooks, in 



from CoBDOnU <<Tebralis of the brain of 

 sheep, \vhii li pr- known ,. 



