Which of these spiders don't have a respiratory system?

Sea spiders, also called Pantopoda are marine arthropods of class Pycnogonida. They are cosmopolitan, found in oceans around the world. There are over 1300 known species, with a leg span ranging from 1 mm (0.04 in) to over 70 cm (2.3 ft). Most are toward the smaller end of this range in relatively shallow depths; however, they can grow to be quite large in Antarctic and deep waters.

Although "sea spiders" are not true spiders, or even arachnids, their traditional classification as chelicerates would place them closer to true spiders than to other well-known arthropod groups, such as insects or crustaceans. This is in dispute, however, as genetic evidence suggests they may be the sister group to all other living arthropods.

Sea spiders have long legs in contrast to small body size. The number of walking legs is usualThey suck nutrients from soft-bodied invertebrates, and their digestive tract has diverticula extending into the legs.

Oxygen is absorbed by the legs and is transported via the hemolymph to the rest of the body. The most recent research seems to indicate that waste leaves the body through the digestive tract or is lost during a moult.