666 



DESCRIPTION OF T^NIA CUCUMERINA. 



body is thin (O'l 5 mm.) and thread-like, and provided with a head, in 

 diameter about twice as much. If the proboscis be extended, it forms 

 upon the apex of the head a club-shaped projection, usually short and 

 rounded, 01 mm. in diameter. The total number of the hooks, which 

 surround the extremity of the rostellum in four irregular rows, is 

 about 60, and of these half belong to the lowest row, which contains 

 the smallest hooks (only about 0-0057 mm. in height, and with a basal 

 disc of the same size). Tlie largest hooks are O'OIS mm. in length, 

 and the diameter of their basal disc is about the same. 

 The posterior half of the rostellum varies in ap- 

 pearance according to the state of contraction, and 

 sometimes looks almost like a thin stalk on the 

 thickened club-shaped, anterior end. The first forty 

 joints are of insignificant length and breadth. They 

 occupy the foremost 6 to 8 mm. of the worm. But 

 beyond that point the joints lengthen so much that 

 they ultimately become four or Jive times as long as 

 they are broad. In the meantime tlie breadth has 

 also considerably increased (to 2 mm.). As their 

 size increases, the joints are gradually more dis- 

 tinctly marked off fro'm each other. The lines of con- 

 nection are constricted, and fie corners rounded off, 

 so that the posterior half of the worm assunus a more 

 and m.ore decidedly moniliform appearance. The, 

 ripe proglottides are of a red colour (on account of 

 the egg-masses shining through), and may he easily 

 detached from the chain. Their number varies, according to circum- 

 stances, from ten to twenty-five, or even more. The male organs attain 

 maturity at about the forty-sixth joint. By the sixtieth joint, the 

 embryonic development is completed ; and at the seventy-fifth the first 

 distinct egg-masses may be seen (0'07 to 02 mm. in diameter). The latter 

 have a roundish discoidal form, and contain, according to their size, a 

 variable number of eggs, on an average two to three dozen. They are formed 

 of a sharply defined firm cement of a brownish colour, and the number 

 in each joint amounts to perhaps from, 350 to 400. The isolated eggs 

 .measure 0'05 mm., and the embryo (with hooks of 0'015 mm.) 0'033 7nm. 



Fro. 347. — Tcenia cucu 

 merina (nat. size). 



The species which we have thus shortly described is by far the 

 most frequent tape-worm in dogs and cats, or at least in those which 

 are reared indoors. It generally lives socially, several hundred speci- 

 mens being sometimes found side by side, and in some cases as many 

 as 2000 (Krabbe). If cystic tape-worms be also present, they are 



always situated farther forwards in the intestine. Hence the worm 

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