S-t-r-e-t-c-h-i-n-g o-u-t

 

So the other day, I was watching this beautiful Six-lined Ribbon Worm (Tubulanus sexlineatus).  It was gliding over a patch of orange sea squirts.  

Along with being curious about what the ribbon worm was up to, I started wondering how long it was.  So I scanned left:

 

And then I scanned to the left some more:

 

And then I scanned to the left some more, and realized that I was looking at a very long ribbon worm.  This might be hard, but can you find additional lengths of the ribbon worm behind the main section?  [You can click on the image below for a slightly larger version.]

 

Given the scale of the photo, I know this is challenging.  Here are some arrows to help you (the rightmost arrow is the head and the leftmost arrow is the last part of the ribbon worm that I could find):

 

And here's a close-up of the lower left corner of the photo to make it easier to spot the left-hand sections of the ribbon worm:

 

 

I estimated that the portions of this Six-lined Ribbon Worm that I could see, from the head to where I could no longer follow it, added up to a length of ~50 cm (~20 inches).  It turns out that this species of nemertean is described as being ~20 cm long, but it can stretch to lengths of over 1 meter!

And since you stayed with me, below is a bonus shot — just enjoying the patterning of the ribbon worm against a colorful backdrop:

 

P.S.  If you're interested, there are some wonderful microscope images of this species in the post called "All lined up" on 20 March 2015.