BUCARDIUM was the epithet applied in the written copy to the members of this genus, to which the _Solen bullatus_ of the 'Systema' was correctly referred. _Mactra_ had not then been separated. C. COSTATUM. _Buc._ sulcis costis elevatis membranaceis. The original description has been somewhat enlarged in the press, by the addition of "brevissimis," "et extrorsum flexis," "fossula distinctus; at vero ille sub anno quasi duplex"; "minus vero ad latera sulcata," moreover, was simply "ad alterum latus": the only expression omitted in printing was "reflexus," which followed "Anus margine." C. CARDISSA. _Buc._ compressum, valvis carinatis, natibus contiguis. "Colum. Aqu. 19. t. 16" (cited also in the 'Systema') was quoted in the MS. from which the "vix," "subcontigui," "remotus, validus, fossula distinctus," were absent. The "Rima" was termed "subrotunda" instead of "cordata." C. HEMICARDIUM. _Buc._ subquadrilaterum: valvulis carinatis, umbonibus distantibus. "Fasciis" was a misprint for the original "facies": "sulcis convexis" was written "sulcis excavato-rugosis." There was no specific appellation. C. MEDIUM. _Buc._ subcordatum subangulatum; valvulis angulatis sulcatis lævibus. The prefatory remarks were the only portion of the printed description to be found in the MS. The species was not named, but was quoted in the 'Systema' before the publication of its details. C. ACULEATUM (misprinted "muricatum"). _Buc._ subcordatum, sulcis convexis, linea cava exaratis, versus apicem dentatis. The intended name was _verum_. C. ECHINATUM. _Buc._ subcordatum, sulcis acutis exaratis linea elevata ciliata aculeis inflexis plurimis. "List. Ang. 188. t. 5. f. 33, Pectunculus echinatus," "Bonan. 2. t. 90," "Gesu. Aq. 131, 132," "Faun. Suec. 1339," "Rondel. Aq. 22," were the original synonyms, to which our author had subsequently added "Klein, 139. t. 10. f. 40." "Alba" followed "gibba"; "parum antrorsum inflexis" was the reading for the printed "erectis subulatis"; "extrorsum" for the "uti extus": "brevioribus. Anus lævis, sutura simplici prominula," "recurvi," "fossula distinctus," were emendations. C. TUBERCULATUM. _Buc._ subcordatum, sulcis obtusis nodosis transversim striatis. "Gualt. t. 71. f. M." was a correct additional synonym. C. ISOCARDIA. _Buc._ cordatum, sulcis imbricatis squamis fornicatis. "Klein, 138. isocardia fragum" had been interpolated by Linnæus; hence the name, which was not in the original. The "fossula distincti" has replaced the earlier "validi." C. FRAGUM. _Buc._ subcordatum subangulatum, sulcis notatis semicirculis elevatis. By the addition of "mala" to the erroneously cited figure of Gualtieri, our author has virtually repudiated it. "Spinosæ" followed "Pruni;" the fallacious "s. rubris" was not present, nor "sæpe" either; "anteriore" stood in the place of "postico," and "postico" in that of "antico." The descriptions of the "rima" and "anus" have been added: "recurvati" and "fossula distincti" were amplifications.