This arrangement is particularly deserving of attention, from its being admitted by the author of the circular system to be the first approach to a perception of that order of affinities which he supposes to pervade the whole animal kingdom. “In the first volume of his celebrated work,” says Mr. Mac Leay, “Lamarck acknowledges that the idea of a simple series constituting the whole of the animal kingdom does not agree with the evident order of nature, because, to use his own words, this order is far from simple; it is branched, and is at the same time composed of several distinct series. He then presumes, that animals offer two separate subramose series, one commencing with the _infusoria_, and leading by means of the mollusca to the cuttlefish (_cephalopoda_), and the other commencing with the intestinal worms, and leading to insects. Now, this notion could only have gained a place in the mind of Lamarck from a conviction by experience of its being an incontrovertible truth. His table of affinities, however confused it may appear, or _subramose_, as it is termed, coincides with the tabular view which I have laid before the public. We have only to join the _radiata_ to the _cirripeda_, and the _annelides_ to fishes, and Lamarck’s table of affinities, with scarcely any alteration, becomes precisely the same as mine[20].” In addition to the various branches of natural history already enumerated as cultivated by this indefatigable and ingenious inquirer, another still remains to be mentioned, to which he communicated a remarkable impulse; namely, the history of fossil shells. This highly important and interesting subject had long attracted the attention of geologists, but owing to the difficulties with which it is invested, it still remained in comparative obscurity. One of the facts most desirable to be ascertained in relation to these remains, was, whether they were identical with species now living, a point which could be determined only by a careful comparison. Applying to this investigation that profound knowledge which he had acquired of recent shells, Lamarck was enabled to illustrate the subject in a most satisfactory manner, and to throw light on some of the most anomalous phenomena which it presents to the inquirer. Besides his extensive acquaintance with the _testacea_, he enjoyed another advantage for entering upon an inquiry of this nature by residing at Paris, the vicinity of which has long been celebrated for the number and variety of its fossil productions[21]. The result of his investigation appeared in several of the earlier volumes of the Annals of the Museum; but the memoir was never brought to a conclusion. It was accompanied with a quarto volume of plates, containing figures of great beauty and accuracy.