ID: Strange Thing on My Glass

[Reefpilot11]

So I have no idea what this thing is just saw it last night. About 3/4" long and white.
Thanks!
<a href="http://s1294.photobucket.com/user/mlongnecker11/media/3F545B75-D1E6-4886-8569-4DBC4D07BC68_zpsy6k5zm3r.jpg.html" target="_blank"><img src="http://i1294.photobucket.com/albums/b610/mlongnecker11/3F545B75-D1E6-4886-8569-4DBC4D07BC68_zpsy6k5zm3r.jpg" border="0" alt=" photo 3F545B75-D1E6-4886-8569-4DBC4D07BC68_zpsy6k5zm3r.jpg"/></a>

 

[viper12775]

Some sort of nudi maybe

 

[IrishTang]

Yup Arminid nudibranch I believe. I had one or two come in on a colony of Cloves I bought awhile back. They seem to hang on the mouth of the closed polyp so I thought they were eating it ( The colony soon declined) though I can't be sure. They multiply quite rapidly too.

 

[Reefpilot11]

The only thing is, it's more flat than a normal nudi is. Almost like some type of flat worm?

 

[IrishTang]

They get real flat when crawling across the glass like that. Doe sit have the 2 rhinophores or antennae on the top of its head? I've seen them lay flat before so you may need to look again.

 

[IrishTang]

Here are a couple pics I got of one.

 

[IrishTang]

They look just like the one in your pic when crawling across the glass, very flat. If it doesn't look like this on it's top it may be some sort of flatworm?

 

[cnreef]

http://www.reefcentral.com/forums/showthread.php?t=1592149

That post has one that looks like yours, although some people in that thread think it's an aefw and others swear it's not. There's also a YouTube video in the thread that shows the same flatworm and someone suggests it may be Dendrocoelum lacteum.