This is stunning footage. Thanks for posting it. I was suspicious about the so-called sea spiders in the video, I have seen sea spiders and they don't look like that. After checking around the web for comments on these videos it turns out the beautiful white animals with dozens of arms that are called sea spiders in the vid are NOT sea spiders but crinoids. These are echinoderms (related to sea urchins and star fish), whereas the sea spiders are probably very distantly related to spiders (their phylogenetic position is not that clear) but they either are chelicelerates (related to horse shoe crabs, spiders, scorpions etc.) or at least close to them. A video showing the actual sea spiders that were seen in the deep antarctic probe is here.

seaspider

(It covers almost the same footage as the other video but also has the sea spiders). The Tunicates (the tall glassy animals) are in the phylum chordata, and counter-intuitively are actually one of the closest related groups to the craniata (i.e us). The similarity is seen in the larva, which are mobile and have a notochord (precursor of the spinal cord).

This is stunning imagery. It gives me the shivers to think about the things that we have seen as a science-based culture in the last 50 years, from inside the cell, to the mountains and plains of Mars, to the deep oceans; and wherever we look something amazing turns up. This alone justifies every dollar spent.

(http://news.nationalgeographic.com/news/2008/02/080219-spider-video-ap.html)