Thus, although the succession be direct in the evolution of its primary characteristics, the prominent features which so present themselves establish the conviction of the existence of connections oblique to the straight line, but all embraced within the normal conditions which bind the group together. These are called relations of affinity. Pursuing them, it is sometimes observed that nature, as it were, returns upon itself, reproducing similar notes in another key. These indications have led philosophical naturalists to surmise that the true arrangement of natural objects is in groups, and not in a straight and continuous line. Several schemes have been suggested for the purpose of giving uniformity to these groups, making them equivalents by associating together the same numbers of allied forms, which again return in a circular series upon themselves, and impinge upon other circles at the parallel points of their circumference by affinities less direct than those which unite them within their own circle. Many novel views and interesting combinations have been thus elicited, showing that very strong affinities lie in very divergent directions, but no system has been hitherto devised which overrules the conflicting difficulties that attend these arrangements. Whatever number may have been adopted to bring nature within this circular system, it has always been found that some, or several members, both in the circles themselves, or in their series, is as yet deficient, and awaits either discovery or creation. The pursuit of such views stimulates profound investigation, and may lead to valuable discoveries that will eventually give a loftier and more philosophical character to the study of natural history than it has hitherto possessed, and make it an attraction to the highest class of mental powers. The key to the universe hangs at the girdle of the veiled goddess; and happy the student who shall achieve possession of it, and unlock the mysteries to the reverential gaze of mankind. The _relation of analogy_ is different in _kind_, although the general affinities which bind a class together are necessarily affinities in the widest construction of the term; but the class being resolved into its elements, those affinities, thus dissevered, no longer retain the uniting links whereby the mass coheres. They, more correctly, stream from their origin in parallelisms rather than in a continuous and uninterrupted current; and these parallelisms present resemblances often of a merely superficial character. As strong an instance as I can adduce is possibly the analogical parallelism of the _Pentamera_ and the _Heteromera_ in the _Coleoptera_, which are, however, bound by the common affinity of being all beetles.