N. PLICATA. _N._ sulcata, labiis profunde dentatis, interiore rotundato, exteriore utrinque dentibus acutis conicis. The variety alluded to was a subsequent addition. The details of the 'Museum' had been quoted, in anticipation, for this species. N. GROSSA. _N._ sulcata labiis dentatis, interiore convexo rugoso. N. CHAMÆLEON. _N._ sulcata, labiis dentatis, interiore rugoso tuberculato. "Habitat in Banda", and "compositis" after "subtilissimis", are the unprinted additions. N. UNDATA. _N._ sulcata, labiis dentatis, interiore rugoso, tuberculato. The erroneous figure of Gualtieri was not cited when the description was drawn up, but added to the details, along with "confluentibus. Spira acuta prominens", when the present name was substituted for the earlier _nebulata_. N. EXUVIA. _N._ sulcata, labiis dentatis, interiore denticulato. HALIOTIS. Testa univalvis, patens, convexa. Spira obsoleta, lateralis. Foramina lateralia pervia. H. MIDÆ. _H._ subrotunda, utrinque nitida. _Humana_ was the intended specific appellation. H. TUBERCULATA. _H._ subovata, rugis transversis tuberculatis. The reference to Lister was an emendation. H. STRIATA. _H._ ovata, transversim rugosa, longitudinaliter striata. No name was attached to either this or any member of the genus, except the first. H. VARIA. _H._ ovata, striis longitudinalibus, majoribus tuberculatis. H. MARMORATA. _H._ ovata, striis longitudinalibus, transversis obsoletis. H. ASININA. _H._ oblonga, extra foramina angulata, striis elevatis. H. PARVA. _H._ ovata, angulo inter foramina et spiram. All the headings in this genus are similar to those in the 'Systema'. PATELLA. Testa conica, convexa. Spira regularis nulla vera. The limits of this genus were precisely those of the printed edition. P. EQUESTRIS. _P._ ungue fornicali nutante. P. NERITOIDEA. _P._ integra ovata, apice subspirali, labio laterali. "Supra" preceded "convexa", and the "fere" was before "apice". P. CHINENSIS. _P._ conica latior lævis, labio interno laterali. This was an addition to the original catalogue. P. PORCELLANA. _P._ basi interne labiata, pone mucronato-subspiralis. P. CREPIDULA was not mentioned in the manuscript. P. SACCHARINA. _P._ margine sinuato, carinata, costis 7. "Pet, Amb. t. 3. f. 3", and "Klein 117. t. 8. f. 4", were additional synonyms: both are in the 'Systema.' P. BARBARA. _P._ dentata, costis 19 elevatis. P. GRANULARIS. _P._ margine dentato, striis elevatis mucronibus imbricatis. The erroneous reference to Gualtieri was not in the original. P. GRANATINA. _P._ margine angulato, striis 11 lævibus. "Interius" was the earlier reading of "subtus". P. TUBERCULATA. _P._ dentata conica tuberculata, postice sima. _Sima_ was the earlier name in the MS., but was erased by Linnæus. P. LUTEA. _P._ integerrima striata, vertice mucronato inflexo. P. UNGUIS. _P._ ovali-oblonga, apice emarginata, mucrone dorsali carinato. _Unguiformis_ was the intended appellation.