A. nobilis Barr. pl. 32, f. 6. Indistinct traces of maculæ. In the figure 6, pl. 31 representing the hypostoma of a young specimen, there are no tubercles at all. If the figures were to be relied upon, it might be assumed, that the tubercles appear at a more mature age.
A. Powisii Salter, pl. 23, f. 6. Two semilunar, narrow tubercular maculæ, their interior apices converging towards the anterior border of the hypostoma.
A. raniceps A., pl. XXVIII, f. 2 c., BR. II, pl. 1, f. 4. A good figure.
A. raniceps var. maxima Br. II, pl. 1, f. 6. Semilunar impressions on a cast and thus far incomplete.
A. striatus Boeck. To this belongs probably A. expansus M. Sars »Ueber einige neue oder unvollständig bekannte Trilobiten» in Isis 1835 p. 333, and especially p. 340 and the following (Bemerkungen über die untere Seite von einigen Trilobiten). Sars there gives a very good description of the exterior side, where he also mentions the two maculæ, pl. IX, f. 9 a, b. (»2 kleine Knoten»), Br. I, pl. VIII, f. 4 a, and Br. II, pl. I, f. 9. These latter figures differ in so far, that the former has the maculæ excavated or rather tubular below, in the latter again they are regular.
A. trinucleorum Br. II, pl. I, f. 16 a large specimen with linear maculæ arranged rectangularly in respect to the longitudinal axis of the hypostoma and both on the same level.
A. tyrannus Murch. Salter in Mem. Geol. Survey, Brit. Foss. Dec. II, 1849 pl. V, f. 4, excellent figure. On p. 2 he says: »there is an oval circumscribed tubercle at the origin of each (fork) most distinct on the inner surface». This figure is again reproduced in the »Monograph», pl. 22, f. 6, where it is said »Two linear tubercles with their interior apices converging towards the posterior margin of the hypostoma».
Asaphus sp., probably A. raniceps, Pompeckj, Trilobitenfauna Ost- and West-Preussens, taf. VI, f. 7. p. 80 »an seinem Hinterrande liegen zwei kleine, flache Höckerchen, die als Reste des Hinterlappens aufzufassen sind»(!?).
We shall now describe the Asaphi which we have been able to examine more in detail.
Asaphus expansus L.