The reference to Klein was not in the original, but "d'Arg. t. 25. f. L." was quoted (as in the twelfth edition of the 'Systema'). The last seven words printed were not in the copy. The intended name was _gibbus_. D. CUNEATA. _Trun._ cuneiformis, marginibus integerrimis. The final remark was not in the copy, where "parva, ovata," preceded "cuneiformis." The then unpublished details were quoted in the 'Systema.' D. SCRIPTA. _Trun._ ovatus lævis scriptus. The erroneous citation of Gualtieri (a misprint for 88. f. Q.) was not in the copy, and, as the figure represents the _D. trunculus_ in the page opposite, I suspect was carelessly placed here by the printer, when our author had inserted it in his revised proof. I suspect this error often occurred, as for instance in _Tellina planata_ and _radiata_, where Gualtieri's figure (added during revision) was attached to the former instead of to the latter. "Margo interne crenulatus," and nearly the entire account of the teeth, were emendations. D. MURICATA. _Trun._ ovatus, striis muricatis, margine denticulato. "Postice solitarii" followed the final "utrinque": "primores" was an emendation. VENUS. This genus (as a whole) was not to be found in the manuscript System. Its components were distributed into three groups, two of which bore names that were subsequently allotted to forms very remote from those therein so designated. CUNNUS. Testa subrotunda. Rima nymphis instructa. Dentes cardinis 4, lateralibus divaricatis versus latera. This contained the bulk of the _Veneres_, all except Nos. 63, 66, and those referred to _Pholas_ and _Chama_. PHOLAS. Testa lenticularis. Rima fissa, destituta nymphis. Dentes cardinis 1 s. 2, marginalis tantum intra anum. _V. Pennsylvanica_, _incrustata_, _punctata_, _edentula_, _exoleta_, _scripta_, _pectinata_, _ziczac_ were its constituents. CHAMA. Testa ovalis cum angulo. Cardo dentibus 4 confertis, quorum unus in singula valvula bifidus. In this were located _V. literata, rotundata, decussata_. V. DIONE. _Cun._ cordatus, antice pubescenti-spinosus. The same references to Petiver, Olearius, and Lister were present as in the 'Systema.' The final remark was an addition. The proposed name was _C. Veneris_. V. MARICA. _Cun._ subcordatus, decussatim striatus, pube lamellosa. V. DYSERA. _Cun._ testa subcordata, sulcis transversis reflexis, labiis concavis incumbentibus. Neither "Huic rugæ, &c.," "lævis," nor the synonym of Lister were in the original. V. CHIONE. _Cun._ subovatus, lævis. The erroneous reference to d'Argenville was not inserted in the MS., from which "lanceolatis," likewise, was absent. V. MACULATA. _Cun._ testa ovato-cordata lævis. "Lanceolata" and "ovato-oblongus" have been additions. The observation that it was difficult to distinguish this shell (which was not named in the MS.) from the following, would mislead one, since the remark referred to two unpublished species, which it originally preceded.