We have seen a number of specimens of this species in the Albany Institute, in Mr. Wetherill's cabinet, and in the Baltimore Athenæum; but in all of them, the abdomen and caudal extremity only remain perfect: from their exact resemblance, however, to the same parts of the A. caudatus, figured by Brongniart, (plate 2, fig. 4, D.) we have no hesitation with regard to their identity. The description which we have given of the _buckler_, supposed to belong to our Asaph, is therefore taken from Brongniart, whose specimens were found at Dudley, the celebrated locality of the C. Blumenbachii.[31] The coriaceous membrane, which extends beyond the lateral lobes and forms the caudal termination of our species, is not covered with minute dots, as in the European fossil; and if a new name is to be applied to it on that account, it may be called _A. glabratus_.[32] M. Wahlenberg, has given the figure of a trilobite which he calls _caudatus_, but ours cannot be mistaken for that species, to which Brongniart has very judiciously applied the name of _A. meucronatus_. [Footnote 31: In the first volume, 2d series, of the Transactions of the Geological Society of London, Mr. Weaver has published some highly interesting observations on the fossils found in Gloucestershire, England. The A. caudatus, he states, is there found in the transition limestone, though very much mutilated. (Vide p. 326.)] [Footnote 32: In the cabinet of G. W. Featherstonhaugh, Esq., I have examined a fine specimen of the A. caudatus, from Dudley, England, but could not perceive the minute dots on the tail, as mentioned by Brongniart.] The conical eye-like protuberances on the head of this species, are very remarkable, and so much resemble the reticulated eyes of the limulus, as to leave no doubt that they once contained the organs of vision. Asaphus Hausmanni. _Brongniart._ Cauda rotundata; cute coriacea tuberculis minimis spinulosis tecta. In De la Beche's Geological Manual, there is a list, of the trilobites which have been discovered in the grauwacke group of rocks. This list we have given in our introduction. Among the trilobites he states that the Asaphus Hausmanni has been found in the United States; as we have not seen the species, and presuming the author to be correct in his locality, we give the following description from Professor Brongniart.