DIMENSIONS OF T^NIA SOLIUM. 



515 



neither in strong contraction nor in great extension, and was there- 

 fore in so far normal. 



The neck was attached to a head 1 mm. broad, and had at first a 

 diameter of 0'45 mm. It exhibited at the end of the first 25 cm. 

 a breadth of 2'2 mm. The number of joints in this length was of 

 course very great. They amounted to 377, of which 112 belonged to 

 the first 2 cm., since the foremost joints were only O'Ol mm. long. The 

 other joints were thus distributed : — the following 6 cm. had 123 joints 

 (of which the last were 0"7 mm. long by 1'2 mm. broad) ; the next 9 

 cm. had 82 (with a maximum length of 1'2 and a maximum breadth of 

 r4 mm) ; the last 8 cm. had 60 (with a maximum length of 1'5 and 

 a maximum breadth of 2'2 mm.). 



In the second 25 cm. the breadth increased from 2-2 mm. to 4'5 

 mm., and the number of joints sank to 129. On the first third there 

 were 50 joints (of which the last were 2 mm. long by 3'3 mm. 

 broad) ; the middle portion bore 42 (with maximum length of 2-2 

 and maximum breadth of 4'3 mm.) ; while the third portion had 37 

 (the last joint being 2'3 mm. by 4'5 mm.). 



The third length of 25 cm. contained on each 8"3 cm. 37, 35, and 30 

 joints respectively — in all 102, of which the last were 6 mm. broad 

 by 31 mm. long. The fourth 25 cm. bore 68 joints, with a terminal 

 length of 4'6 and a breadth of 6'6 mm. 



The 5th 25 cm. bore 49 joints, of which the last were 6 '5 mm. long by 6 '3 broad. 



6th 

 7th 

 8th 

 9th 

 Last 



37 

 29 

 25 

 23 

 22 



7-5 



9 '5 



11-3 



12-2 



13 



6-3 



6 



5-6 



5 



4-5 



In all, therefore, the worm had 861 joints, but these were so different 

 in size and development, according to position, that the different parts 

 of the chain looked very different. Thus the anterior half consisted 

 of joints whose breadth was decidedly greater than their length, but 

 always decreasingly so, till about tlie middle of the body the joints 

 were approximately square. In the second half the length was greater 

 than the breadth, and that increasingly so, since the breadth diminished 

 in a marked manner posteriorly. By the middle of the first metre 

 the ratio of the breadth to the length was as 1 : 0'5, in the middle of 

 the last metre as 1:2. The greatest absolute breadth occurred at a 

 short distance behind the middle of the body. 



We need hardly note, after what was said of Tcenia saginata 

 (p. 431), that there is a direct connection between the form of the 

 joint and the developmental stage reached by the sexual organs, and 

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