The first part of this investigation deals with the stratigraphical results obtained with help of Dasycladaceae in the Urgonian limestones of Barremian and lower Aptian age. The distribution of Dasycladaceae is described with reference to five zones of Orbitolinidae, previously defined by SCHROEDER & al. (1968), and to some finds of Ammonites. As a result the Barremian can easily be differentiated from the lower Aptian. On the contrary, it is more difficult to differentiate the upper Barremian from the lower Barremian by means of Dasycladaceae only. Depositional environments are briefly described. In the lower Barremian, the abundance and taxonomical variety of Dasycladaceae were apparently related to external infralittoral (shallow shelf edge) environments. The second part of this investigation deals with taxonomical study. Pseudoactinoporella fragilis, n. gen., n. sp., is a phloiophorous new genus which occurs in the Barremian and in the lower Aptian. Heteroporella ? paucicalcarea, n. sp., whose taxonomical characters are not yet fully understood is common in the Barremian and rare in the lower Aptian. Pianella muehlbergii (LORENZ) is described on the basis of an abundant material of Barremian and lower Aptian ages, and a neotype is designated. The other following species are briefly described and illustrated: Verticilloporella dalmatica RAVIV & LORCH; Likanella ? danilovae RADOICIC; Triploporella aff. fraasi STEINMANN; Clypeina pejovici RADOICIC; Pianella genevensis CONRAD; Pianella cemi RADOICIC; Pianella melitae (RADOICIC); Pianella ? aff. pygmaea (GUEMBEL).