A large number of well preserved radiolarian faunas have been found in Early Carboniferous rocks ( Pericyclus-Alpha to Goniatites-Stufe) of the “Rheinisches Schiefergebirge” and the Frankenwald (Germany). The growing number of fossil faunas makes it possible to show evolutionary tendencies of certain taxa within these stratigraphic levels. In the course of the Early Carboniferous a continuous transformation of the general character of the radiolarian faunas took place. This transformation generally tended towards an increase of the surface area of the skeletons. We see trends within the following groups. The Entactiniidae Riedel 1967 show two separate tendencies, one being a considerable lengthening of their spines, the other being a reduction of spine-number connected with a strong increase in size of the remaining spines. The Albaillellidae Deflandre 1973 show a documentable change in the morphology of their cavea as well as their stapia. The Latentifistulidae Nazarov and Ormiston 1983 evolve from ancestral narrow-rayed forms to broad-triradiate and triangular forms. The “phacoid” forms of the group Sphaerodiscus Won 1983/ Eostylodictya Ormiston and Lane 1976 show a progressive overgrowth of the central shell by peripheral concentric rings and a simultaneous change in morphology from flat-discoidal to lensoid.