It will be observed that they are grouped under the three principal heads of Arches, Loops, and Whorls, and that under each of these heads some analogous patterns as ~4~, ~5~, ~7~, ~8~, etc., are introduced and underlined with the word "see" so and so, and thus noted as really belonging to one of the other heads. This is done to indicate the character of the transitional cases that unite respectively the Arches with the Loops, the Arches with the Whorls, and the Loops with the Whorls. More will follow in respect to these. The "tented arch" (~3~) is extremely rare on the thumb; I do not remember ever to have seen it there, consequently it did not appear in the plate of patterns in the _Phil. Trans._ which referred to thumbs. On the other hand, the "banded duplex spiral" (~30~) is common in the thumb, but rare elsewhere. There are some compound patterns, especially the "spiral in loop" (~21~) and the "circlet in loop" (~22~), which are as much loops as whorls; but are reckoned as whorls. The "twinned loop" (~16~) is of more frequent occurrence than would be supposed from the examination of _dabbed_ impressions, as the only part of the outer loop then in view resembles outside arches; it is due to a double separation of the ridges (Plate 4, Fig. 8), and a consequent double interspace. The "crested loop" (~13~) may sometimes be regarded as an incipient form of a "duplex spiral" (~29~). The reader may also refer to Plate 16, which contains what is there called the C set of standard patterns. They were arranged and used for a special purpose, as described in Chapter XI. They refer to impressions of the right hand. As a variety of Cores, differing in shape and size, may be found within each of the outlines, it is advisable to describe them separately. Plate 8, Fig. 14 shows a series of the cores of loops, in which the innermost lineations may be either straight or curved back; in the one case they are here called rods (~31~ to ~35~); in the other (~36~ to ~42~), staples. The first of the ridges that envelops the core, whether the core be a rod, many rods, or a staple, is also shown and named (~43~ to ~48~). None of the descriptions are intended to apply to more than the _very end_ of the core, say, from the tip downwards to a distance equal to two average ridge-intervals in length. If more of the core be taken into account, the many varieties in their lower parts begin to make description confusing. In respect to the "parted" staples and envelopes, and those that are single-eyed, the description may further mention the side on which the parting or the eye occurs, whether it be the Inner or the Outer.