The present heading agrees with the subsequent details, which could not be affirmed of the printed one borrowed from the 'Systema.' The MS., in some degree, clears up the extraordinary confusion in which the Linnean species was enveloped. There were two _N. albumens_ in the written copy. The shell here described (assuredly not the lobed _albumen_ of the 'Systema') was originally termed _hepatica_ or _luteola_ (for both had been erased). The true _albumen_ was described as "edentula subrotunda, umbilico subcordato labri interioris lobo explanato" and the only figure referred to was "Rumph. t. 22. f. B." "Klein 13. Platystoma vitellum compressum" was also mentioned. This description was suppressed, and the other species retained, with the erroneous designation, and the faulty synonymy, attached. Nor was this the only change. In order to include the _Natica vitellus_ of authors ("Rumph. t. 22. f. A. Valvata lævis prima s. vitellus" had been quoted by our author) the "aut lutea", "aut maculis albis", had been added to the earlier description: so, likewise, had been "Apertura rotundata, semicordata", and "glabrum, planiusculum, nitidum." I suspect, then, that whilst the ideal of the _albumen_ of the 'Systema' was any hemispherical or flattened _Natica_ with a labial lobe (such as _Nat. albumen_, _didyma_, _olla_, _&c._), the _albumen_ of the 'Museum', as printed, was composed of _Natica rufa_ ("Rumph. 22. f. D." was quoted in the MS.) and _vitellus_ (for A, not B, of Rumphius was the letter indicated in the MS.). N. MAMMILLA. The entire account of this common shell was added in the Linnean handwriting. The inappropriate "aut lutea" was not at first present. N. CORONA. _N._ edentula, simplici spira spinosa. "Pet. Amb. t. 3. f. 4.", a mere copy of the Rumphian figure, was also quoted. The 19 in the reference to d'Argenville was a misprint for the written 10. _N. spinosa_ was the intended designation. N. RADULA. _N._ edentula sulcata, tuberculis æqualibus. The valvata granulata of Rumphius (t. 22. f. M.) was referred to at illustrative. N. CORNEA. _N._ edentula, obsolete striata. N. BIDENS. _N._ "Obsoletis" followed "duobus": the name had been written subsequent to the description. N. VIRGINEA. _N._ subedentula ovata lævis. "Dentibus pluribus minutissimis" preceded "oris"; "Pet. Gaz. t. 11. f. 3" was in the place of the delusive figure of d'Argenville: the variety d was a subsequent addition. N. POLITA. _N._ lævis, labiis dentatis. The 1 in the synonym of Rumphius was a misprint for the written I. N. PELERONTA. _N._ striata, labiis dentatis, interiore planiusculo rugoso. The erroneous synonym was added, along with the name peleronta, to the written details: _N. rufa_ was the original appellation. N. ALBICILLA. _N._ striata, labiis subdentatis, interiore tuberculato. N. HISTRIO. _N._ sulcata, transversim striata, labio interiore dentato. The name, and the synonym, were added by Linnæus to the written details.