I came across this just now (researching horseblocks!):
Berenger, History and Art of Horsemanship (1771), Vol. 1, pp. 64, 65 wrote:The horseblocks which they used, were composed of stone, or wood ; and were in great abundance upon all the roads ; the Roman people, according to Plutarch, being under much obligation to Gracchus, who caused these conveniencies to be placed at proper distances for the use of travellers. Porchachi, in his Funerali Antichi, has preserved an inscription, in which one of these horseblocks (suppedaneum) is jestingly dedicated by Crassus to his mule, and was erected in the road from Tivoli to Rome.
Dis pedib. Saxum.
Ciuciae dorsiferae & cluniferae
Ut insultare et desultare commodetur.
Pub. Crassus mulae suae Crassae bene ferenti
Suppedaneum hoc cum rifu pos.
Vixit annos XI.
It is impossible to translate this inscription so as to make it intelligible to the English reader ; to those who are acquainted with the language in which it is written, I will, with all deference, submit a conjecture, which may attempt to give it some meaning. It seems to be ludicrous, and designed, perhaps, as a parody upon the known form and stile of lapidary inscriptions. Dis ped. is for Dis pedibus, and is opposed to Dis manibus, allowing the pun between manes and manus, Saxum is contrasted to sacrum, the usual word in epitaphs. Beneferenti is used instead of benemerenti, a word frequent in monumental formularies ; and the cum risu seems to justify the construction, and confess that the inscriber was burlesquing, and in joke.
Non adusquè rectum, meâ sententiâ. Sic converto [quo "cruciae", non "ciuciae", lego]. Quid putas?
It's not entirely so, I think. I translate it this way [reading "cruciae" for "ciuciae"]. What do you reckon?
Stone [dedicated] to the foot gods, with back and hindquarters cross-support to aid mounting and dismounting. Publius Crassus erected this mounting block as a joke for the good services of his mule Crassa. It lived eleven years.
Photo of 'modern' horseblock at a roadside// Photographica suppedanei moderni propter viam imago:
http://v3.cache1.c.bigcache.googleapis.com/static.panoramio.com/photos/original/29456105.jpg?redirect_counter=1 et hîc http://en.wikipedia.org/wiki/Mounting_block