Calymene Blumenbachii. _Brongniart._ Cast No. 1. Clypeo rotundato, tuberculis sex distinctis in fronte; oculis in genis emintissimis; corpore tuberculato. In this species the upper lip presents a furrow parallel to its edges. The lip is straight. The cheeks are a little projecting. There are six rounded tubercles on the front, and fourteen articulations on the back; the tail is small, and the shell is covered with small rounded tubercles of unequal sizes. The above is Professor Brongniart's description of this trilobite, which is the famous Dudley fossil described and figured by Littleton, in the Philosophical Transactions, (London) in 1750. According to Dalman, several distinct European species have been published under this name. The true C. Blumenbachii, he says, has thirteen articulations to the abdomen, and about eight to the tail. In the cabinet of G. W. Featherstonhaugh, Esq., we have examined a fine perfect specimen from Dudley,[13] in which there is fourteen abdominal joints. There can be no doubt, however, that several species have been confounded under the name of C. Blumenbachii; Dalman's C. Tuberculata and C. Pulchella are, we think, distinct from it, though he has marked them only as varieties. [Footnote 13: This famous trilobite, once formed a part of the cabinet of Mr. Parkinson, the distinguished author of the "Organic Remains," and is accurately figured on one of the plates of that splendid work. At the sale of the late Mr. Parkinson's fossils, it was purchased by Mr. Featherstonhaugh,] The true C. Blumenbachii, no doubt, abounds in North America, and is one of the few examples of the occurrence of an identical species on both continents. The late Abbe Correa sent a perfect specimen to Brongniart, from the vicinity of Lebanon, in the state of Ohio. We have also seen a number of specimens from that state, which could not be distinguished from the Dudley trilobite. Our model was taken from a specimen found at Trenton Falls, in the state of New York. The three following species found in the United States, will no doubt be considered by many as mere varieties of the C. Blumenbachii; we have ventured, however, to call them by distinct names. Calymene Callicephala.[14] _Green._ Cast No. 2. [Footnote 14: From two Greek words, which signify "beautiful head."] Clypeo antice attenuato, figura liliiformi in fronte depicta; oculis minimis; abdomine quatuordecim articulis; corpore plano.