this is my first time posting here. I was in my Zoology lab doing a dissection on a Crayfish when I noticed these hairlike structures within the gills. They were very "snappy" and fine, and would break off if I pulled hard enough. I put some on a wet mount under a dissecting microscope, but my Lab prof and the parasitologist could not identify it. We put it under a compound microscope and thought maybe it is an animal but we couldn't definitively say it had no cell well. My profs thought it was an animal, with setae, but I would really like to know what it is

Edit here are the images:microscope image microscope image 2

  • $\begingroup$ Were the hair things coming off the central tubes paired? It almost looks like they are, but I'm not sure. $\endgroup$ – Resonating Mar 19 '15 at 3:01
  • $\begingroup$ I had to concede on this one after a lengthy query. If we had a look at either end of whatever it is it'd make identification a tad easier. $\endgroup$ – CKM Mar 31 '15 at 22:23

My best guess would be Trematoda which is a fluke worm that infects mollusk. I would think this is the larval stage of cercaria which is free swimming and develops in the mollusk and then moves on to infect others.

Here are some different images of a cercaria:



In this YouTube video you will see what is known as a "Rat King" which is just a ball essential of Trematoda. Here is a screenshot


  • $\begingroup$ It would be nice that the images from the question have some scale. The first picture of a trematode cercariae has a view of 0.267 mm across according to the source. From the average size of trematode cercaria, perhaps it's a little too small compared to the 'hair' structure on the (visible fine structures of) crayfish gills? $\endgroup$ – SYK Mar 31 '15 at 7:49
  • $\begingroup$ @SYK If you click edit, you will find the sources to the images. There was no scale provided. I just made do with what was available. The size of the rat king is appears to be an equivalent size. $\endgroup$ – dustin Mar 31 '15 at 13:58
  • $\begingroup$ @dustin OK, not that your image is not cool. I was just looking at the seemingly identical image at networlddirectory.com/blogs/permalinks/7-2006/… $\endgroup$ – SYK Mar 31 '15 at 18:58
  • $\begingroup$ I know this post received a bounty 4 years ago, but I really am not at all convinced this is a correct answer... $\endgroup$ – theforestecologist Mar 13 at 3:00
  • $\begingroup$ @theforestecologist if you read the first sentence I wrote, I state it is a guess. With the available information giving, that was my best guess. $\endgroup$ – dustin Mar 16 at 4:41

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