The basal plate of these Cortiniscida exhibits the same important differences as in the preceding Semantiscida, either one, or two, or three pairs of basal gates being developed. But there occur also in some species (mainly in _Cortiniscus_) only three basal gates, an odd anterior (between the two pectoral feet and a connecting horizontal bar), and two paired posterior (between the two pectoral and the odd caudal foot). It requires further accurate researches to solve the important problem, what the true homologies of these typical basal pores and the separating bars are in the different genera of Semantida. In _Semantiscus_ there are three pairs of basal pores in the horizontal seal, corresponding to those of _Semantidium_ and the radial rods or bars between, these are the basal parts of the six radial feet; therefore the odd caudal foot (_t_) seems to be the posterior, and the odd sternal foot (_z_) the anterior prolongation of the basal part of the primary sagittal ring; the two paired anterior or pectoral feet (_p__{1}, _p__{11}) the prolongations of the coracal rods (_e_) and the two paired posterior or tergal feet (_t__{1}, _t__{11}), the prolongations of the scapular rods (_g_). But it is not yet certain whether these six radial feet and the separating gates of the basal plate are all the same and truly homologous in all six-radiate NASSELLARIA. In every case the comparative study of the Semantida is of the highest value for the accurate knowledge of the MONOPYLEA. {956}_Synopsis of the Genera of Semantida._ ------------------------------------------------------------------------- I. Subfamily Semantiscida. Basal ring without typical, regularly disposed basal feet (no cortinar feet). ------------------------------------------------------------------------- { Two basal pores, 407. _Semantis_. Only two, four, or six { basal pores (no dorsal { Four basal pores, 408. _Semantrum_. and ventral pores). { { Six basal pores, 409. _Semantidium_. Besides four basal pores, also apical pores or dorsal and ventral pores along the whole ring, 410. _Clathrocircus_. ------------------------------------------------------------------------- II. Subfamily Cortiniscida. Basal ring with typical, regularly disposed basal feet (cortinar feet). ------------------------------------------------------------------------- { One odd caudal foot and Three basal feet. { two paired lateral { feet, 411. _Cortiniscus_. { Two sagittal and two Four basal feet. { lateral or pectoral { feet, 412. _Stephaniscus_.