The Primary Larva of the Sitares 



space as the horny arches. At the same 

 time the anal segment emerges from the 

 sheath formed by the eighth; the anus, 

 in turn, is stretched into a nipple ; and 

 the two points of the penultimate ring rise, 

 at first slowly, and then suddenly stand up 

 with an abrupt motion similar to that of a 

 spring when released. In the end, these two 

 points diverge like the horns of a crescent. 

 Once this complex apparatus is unfolded, the 

 tiny creature is ready to crawl upon the most 

 slippery surface. 



The last segment and its anal button are 

 curved at right angles to the axis of the 

 body; and the anus comes and presses upon 

 the surface of locomotion, where it ejects a 

 tiny drop of transparent, treacly fluid, which 

 glues and holds the little creature firmly in 

 position, supported on a sort of tripod 

 formed by the anal button and the two cirri 

 of the last segment. If we are observing the 

 animal's manner of locomotion on a strip of 

 glass, we can hold the strip in a vertical 

 position, or even turn it upside down, or 

 shake it lightly, without causing the larva to 

 become detached and fall, held fast as it is 

 by the glutinous secretion of the anal button. 



If it has to proceed along a surface where 

 there is no danger of a fall, the microscopic 

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