The erased nomenclature of the species, however, was very dissimilar, and was scrupulously based upon a supposed identity of the specimens with those delineated by Rumphius, Klein, and d'Argenville. Assuredly at that period of his career, our author entertained the same profound respect for the laws of priority which is professed by all modern naturalists; and I hesitate not to affirm that, from the crude and inharmonious theories of his predecessors, he eliminated a system of Conchology that was better suited to the requirements of the age he lived in than any more elaborate arrangement would have been. For simplicity attracts the student, whom a more complex (even if more natural) method would repel; and for the collection of an adequate mass of materials wherewith, eventually, to build up a more symmetrical and widely-based structure, a multitude of comparatively unskilled labourers is more efficacious than a small knot of the most erudite architects. Before inviting the attention of my readers to the original headings of the 'Museum Ulricæ,' and to my brief account of the variations in the written copy from the text of the printed version, I must premise, that it has not been my practice invariably to notice, in the summary, such trifling differences of construction as the preferential use of the ablative for the nominative case, where the verbal change involved no alteration of the precise meaning. MUSEUM LUDOVICÆ ULRICÆ REGINÆ. CONCHYLIA. CHITON, LEPAS. Nothing relating to these two genera was found in the copy. PHOLAS. The _Pholas_ of the manuscript is perfectly dissimilar to that of the 'Systema.' Our author had evidently, when he first wrote the 'Museum Ulricæ,' not appreciated the remarkably striking characteristics of this group, having located the only species he then knew (for _P. candidus_ seems a subsequent discovery) with the _Solens_. P. CANDIDUS. Not mentioned in the manuscript. P. CRISPATUS. _Sol._ ovatus, obtusissimus, cardinis dente depresso rotundato. The Appendix to Lister was not cited; "Habitat in Anglia, Suecia," was appended to the description, which in many respects was inferior to the published one. The account of the hinge was merely "Cardo dente dilatato rotundato extus excavato." MYA. The three incongruous forms assorted as _Myæ_ were not so united in the MS.; the second being very properly placed with the _Mussels_, the other two ascribed to _Solen_. M. LUTRARIA. _Sol._ ovali-oblongus, cardine laterali dilatato semiorbiculato. In lieu of the reference to Lister (whose work does not appear to have been consulted by our author at the period when this portion of his manuscript was written), plate 45, figure N, of Rumphius was quoted as illustrative. The published account of the hinge is much more complete than the written one, which was apparently drawn up from a worn specimen; it ran as follows: "Cardo extus vix gibbus, intus constans laminis 2 semiorbiculatis concavis introrsum spectantibus."