Pl. VI fig. 11. The hypostoma somewhat reminds of that of Calymmene, has projecting angles and a prominent knob below the straight anterior border. The two oblique and oblong macula are tubercular and placed near the lateral borders. This hypostoma is upon the whole much related to that of Phillipsia and Proetus. =Phillipsia= PORTLOCK. DE KONINCK figured a hypostoma of Phillipsia in his »Description des Animaux Foss. de Belgique» as Cyclus Brongniartianus pl. LII fig. J and NOVÁK in III figs. 6, 7 copied it and corrected the error. It is provided with two globular maculæ united by a curved ridge. _Phillipsia Eichwaldi_ WOODW. NOVÁK III fig. 5 a hypostoma with globular maculæ. We have been able to examine three different, unnamed or undeterminated species, which we distinguish by numbering them. _Phill. No. 1_ from the Keokuk group of Crawfordsville, N. America. The hypostoma is broader than in the other species. The nearly horizontal elongated maculæ placed near the median line, close to the lateral margins. _Phill. No. 2_ (pl. VI, figs. 15-18) probably from the Carboniferous formation of Belgium is of a lengthened form. The elliptic maculæ in the groove, below the central elevation. They are smooth and surrounded by a flat border. The cephalic eyes are much destroyed, but seem to have consisted of somewhat semi-prismatic lenses or prisms of the same type as Dysplanus. _Phillipsia No. 3_ (pl. VI figs. 12-14) from the Carboniferous strata of Beeren Eiland communicated by Hr J. G. ANDERSSON. It comes near the preceding, is lengthened, but has broader and shorter anterior wings and the inferior surface just above the posterior border peculiarly pitted. The macula lying above this pitted field are ovate. The lenses of the cephalic eye are hemispheric on the surface. =Platymetopus= ANGELIN. =Pl. planifrons= ANGELIN. Pl. IV figs. 50, 51. This genus may well be kept distinguished from Lichas in consequence of its peculiar hypostoma and its still more peculiar maculæ, not to remind of the other deviating features. The maculæ lie at the end of narrow, sigmoid grooves of their own above the long transverse groove, separating the posterior border from the anterior elevated moiety. They are elongated, curved and entirely covered with a great number of irregular lenticles, translucent through the thin covering membrane. =Pliomera= ANG. _Pliomera Törnquisti_ HOLM in Trilobit. Dalecarliens p. 5 fig. 2. While Pl. Fischeri and Pl. actinura not have any hypostomic maculæ, this species, which Dr. HOLM with some doubt joins in the same genus, has a hypostoma, which as to its general shape resembles that of both the mentioned species, evenly rounded at its posterior border, with a shallow groove encircling the central field. A little below the horizontal diameter of this the maculæ stretch obliquely inwards and downwards. They rest on a little elevation and are elongate, anteriorly acuminated. The figure on HOLM'S plate does not show the maculæ.