"Et omnia cadem" followed "sanguineæ"; "striis compressis echinatis" was not present; "color pallidior" was in the place of "concolor." O. PUSIO. _Pec._ radiis 40 filiformibus. O. GLABRA. _Pec._ radiis 10 lævibus planiusculis, internis striis elevatis duplicatis. Gualtieri's rude drawing was not quoted. O. OPERCULARIS. _Pec._ radiis 20 subrotundis, decussate striato-scaber, operculo convexiore. O. GIBBA. _Pec._ radiis 20 glabris, gibbus. Brown's drawing was not quoted. O. FLAVICANS. _Pec._ radiis 8 striatis, margine altero rotundato. As in the 'Systema,' the next two shells, along with this, formed a group distinguished as having the "Valvulis altero latere magis gibbis." No names had been appended to this, the three preceding, and the two following species. O. FASCIATA. _Pec._ radiis 20, auriculis æqualibus exoletis. The "gibba" of the borrowed diagnosis was not, it may be observed, in the original. O. LIMA. _Pec._ radiis 22, imbricatis squamis, altero margine rotundato, auriculis obliteratis. The "gibba" of the borrowed heading was not in the original diagnosis. The final remark was likewise absent. O. ISOGNOMON. The entire account of this species was added to the copy in the Linnean handwriting. "Klein, 128. t. 8. f. 15. Isognomon" and "Cardo ut ephippo" had been omitted in printing. O. MALLEUS. _O._ trilobum. "Transverso ad marginem" was a subsequent addition. O. FOLIUM. _O._ ovatum, lateribus obtuse plicatum. Klein's copy (t. 8. f. 22.) of the indicated figure in Rumphius was cited, in the handwriting of Linnæus: the "cavitate conica" was an emendation. O. EDULE. _O._ subrotundum semiorbiculatum, valvula altera plana integerrima. There was no semicolon after "opaca," but a comma after "latiore." The original sole synonym was the omitted one of "Gualt t. 102. f. B." O. SEMIAURITUM. _O._ semiauritum ovatum læve, basi obliqua. Linnæus himself had added this species to the earlier catalogue. O. EPHIPPIUM. _O._ submembranaceum curvum, cardine octosulcato. In addition to the published _Ostreæ_, the following description of the shell subsequently termed _O. perna_ (Syst. ed. 12.) was found in the manuscript:-- _O._ rugosum, inæquale, tumidiusculum, cardine octocrenato. Testa perniformis, obovata, substantia ligni antiqui, tumidiuscula, superficie obsolete rugosa, inæquali interne livida. Cardo transversus, margine inflexo, notatus crenis obtusis circiter 8. ANOMIA. The single species here mentioned was comprehended in _Ostreum_. A. PLACENTA. _O._ orbiculatum planum pellucidum. Reference was made, by a long periphrasis, to plates 225, 226 of Lister's 'Historiæ'; Seba was not quoted: "intra discum testæ adnatis" was absent. MYTILUS. Testa opaca, læviuscula. Cardo nullis dentibus instructus, sed fossula obliqua intra marginem.