sentences:  The gut has a relatively small diameter, and there are four pairs of relatively small digestive sacs (or caeca) in the cephalon only, and no branches towards the edge of the cephalon (unlike "Naraoia").There are 25 limb pairs with two branches on a common base, like "Naraoia" and trilobites.The outer branch (or exopod) has many parallel long fine flattened side branches (setae) that probably functioned as gills with a large surface area.