almost like a Homalonotus, and the hypostoma of which has been partly delineated in this memoir, seems to be the real one. They differ both in the shape of the hypostoma as well as in other respects. =Barrandia= MAC COY. According to SALTER Monogr. pl. 19 fig. 9 his B. Portlocki, of which there is a fragmentary and broken hypostoma, shows feeble traces of oblique macula, nearly in the fashion of Asaphus. In the description at page 139 is told about »the usual pair of tubercles». =Bronteus= GOLDFUSS. BARRANDE delineates the maculæ on the hypostoma of _B. palifer_, Tab. 45 fig. 17, _B. planus_, Tab. 48 fig. 7, and in the supplementar volume of _B. rhinoceros_, Tab. 9 f. 16, _B. furcifer_, Tab. 11 fig. 16, but there is not the slightest indication of granulation on any of them, nor is there in the descriptions, generic or specific, the least mention made of the tubercular maculæ. It is also remarkable that in the works of ANGELIN and NOVÁK where several hypostomas belonging to species of this genus are delineated, not a single one shows these tubercles. We shall now continue the descriptions of the Swedish Brontei, already begun with Br. polyactin in the introductory part of this memoir. =Bronteus irradians= LINDSTR. Pl. II figs. 4-5. has a hypostoma that much resembles that of Br. polyactin. In its general shape it is similar and the two concentric grooves with the two maculæ placed in the same way, just below the superior groove. These maculæ are much larger than in Br. polyactin, nearly thrice their size. They are also more ovate or rather like a bean, the smooth surface is larger and the granulated spot restricted to a more narrow space forming an oblique patch. The granules or lenses are also individually larger than in the allied species, double their size or 0,06 millimeters. We have not succeeded in making sections of the cephalic eye nor of the maculæ. =Br. platyactin= ANGELIN. Pl. II f. 14-19.