The areas outside the axis are almost flat. Between the front of the glabella and the border, is a somewhat convex area of the cheek that is comparable in length (along the midline) to the occipital ring. In well preserved specimens the cheeks in front of the eye are adorned with very fine ridges (or striae) that probably represent parts of the digestive system (see Kordule, 2006, p. 283, figure 2.a/f). The eye ridges are threadlike, evenly curved, extending from the anterior corners of the glabella to halfway the genal angles, while the visual surface makes an abrupt angle, is shaped like a bracket parallel to the midline and ±⅛ of the length of the cephalon. Like in most trilobites, the division between the outer free cheek (or librigena) and the inner fixed cheek (or fixigena) is a line (or suture) where the exoskeleton splits to assist in moulting. It always follows the inside of the visual surface of the eye. In Ptychoparia, the part of this suture behind the eye cuts to the posterior margin just to the inside of the genal spine (or the suture is gonatoparian), and the part in front of the eye diverges from the midline. There is a spine in the back corners of the cephalon (or genal spine) that reaches approximately to the third thorax segment, and is confluent with the outer margin of the cephalon. The articulate midsection of the body (or thorax) has 13 (P. striata) or 14 (P. dubinka) segments. Tail shield (or pygidium) is slightly over half as wide as the cephalon (a state called micropygous). The pygidial axis (or rachis) has 5 or 6 rings and a termination and 4 or 5 ribs in the outlying pleural regions. The pygidium in Ptychoparia lacks a border. References Ptychopariidae Prehistoric life of Europe Ptychopariida genera Cambrian trilobites