The word loculamentum is explained in a passage of Columella, in which he gives directions for the making of dovecotes:

Let small stakes be placed close together, with planks laid across them to carry cells (loculamenta) for the birds to build their nests in, or sets of pigeon-holes made of earthenware[76].

In a second passage he uses the same word for a beehive[77]; Vegetius, a writer on veterinary surgery, uses it for the socket of a horse's tooth[78]; and Vitruvius, in a more general way, for a case to contain a small piece of machinery[79]. Generally, the word may be taken to signify a long narrow box, open at one end, and, like nidus and forulus, may be translated "pigeon-hole." Seneca, again, applies the word to books in the passage I have already translated, and in a singularly instructive manner. "You will find," he says, "in the libraries of the most arrant idlers all that orators or historians have written—bookcases (loculamenta) built up as high as the ceiling[80]."

Pegmata, for the word generally occurs in the plural, are, as the name implies, things fixed together, usually planks of wood framed into a platform, and used in theatres to carry pieces of scenery or performers up and down. As applied to books "shelves" are probably meant: an interpretation borne out by the Digest, in which it is stated that "window-frames and pegmata are included in the purchase of a house[81]." They were therefore what we should call "fixtures."

A pluteus was a machine used by infantry for protection in the field: and hence the word is applied to any fence, or boarding to form the limit or edge of anything, as a table or a bed. Plutei were not attached so closely to the walls as pegmata, for in the Digest they are classed with nets to keep out birds, mats, awnings, and the like, and are not to be regarded as part and parcel of a house[82]. Juvenal uses the word for a shelf in his second Satire, where he is denouncing pretenders to knowledge:

Indocti primum, quamquam plena omnia gypso
Chrysippi invenias, nam perfectissimus horum est
Si quis Aristotelem similem vel Pittacon emit
Et iubet archetypos pluteum servare Cleanthas[83].

In the first place they are dunces, though you find their houses full of plaster figures of Chrysippus: for a man of this sort is not fully equipped until he buys a likeness of Aristotle or Pittacus, and bids a shelf take care of original portraits of Cleanthes.

This investigation has shewn that three of the words applied to the preservation of books, namely, nidus, forulus, and loculamentum, may be rendered by the English "pigeon-hole"; and that pegma and pluteus mean contrivances of wood which may be rendered by the English "shelving." It is quite clear that pegmata could be run up with great rapidity, from a very graphic account in Cicero's letters of the rearrangement of his library. He begins by writing to his friend Atticus as follows:

I wish you would send me any two fellows out of your library, for Tyrannio to make use of as pasters, and assistants in other matters. Remind them to bring some vellum with them to make those titles (indices) which you Greeks, I believe, call [σιλλυβοι]. You are not to do this if it is inconvenient to you[84]....