Salve Scarlatti!
This does not have to be an error in the key. Using Google to make a site-search of TheLatinLibrary.org via
site:thelatinlibrary.com "a cornu dextro" I found several instances of similar phrases. It seems that both
in dextro cornu and
a dextro cornu are valid.
Two samples from Caesar:
- At totis fere castris a fronte et a sinistra parte nudatis, cum in dextro cornu legio XII. et non magno ab ea intervallo VII. constitisset, omnes Nervii confertissimo agmine duce Boduognato, qui summam imperii tenebat, ad eum locum contenderunt; quorum pars ab aperto latere legiones circumvenire, pars summum castrorum locum petere coepit. (Bellum Gallicum, 2.23)
- Cum hostium acies a sinistro cornu pulsa atque in fugam coniecta esset, a dextro cornu vehementer multitudine suorum nostram aciem premebant. (Bellum Gallicum, 1.52)
There are even instances without any preposition.
I guess that this is an instance of that sense of "abs, a" which is listed in Lewis & Short's
A Latin Dictionary as follows:
3. To denote the side or direction from which an object is viewed in its local relations,=a parte, at, on, in: utrum hacin feriam an ab laeva latus? Enn. ap. Plaut. Cist. 3, 10 (Trag. v. 38 Vahl.); cf.: “picus et cornix ab laeva, corvos, parra ab dextera consuadent,” Plaut. As. 2, 1, 12: clamore ab ea parte audito. on this side, Caes. B. G. 3, 26, 4: Gallia Celtica attingit ab Sequanis et Helvetiis flumen Rhenum, on the side of the Sequani, i. e. their country, id. ib. 1, 1, 5: “pleraque Alpium ab Italia sicut breviora ita arrectiora sunt,” on the Italian side, Liv. 21, 35, 11: “non eadem diligentia ab decumuna porta castra munita,” at the main entrance, Caes. B. G. 3, 25 fin.: “erat a septentrionibus collis,” on the north, id. ib. 7, 83, 2; so, ab oriente, a meridie, ab occasu; a fronte, a latere, a tergo, etc.
Personally, I find it rather difficult to relate to this use.
Has anyone an idea, whether there are clear rules when to use the preposition
in or
a, ab under these circumstances? I guess it depends on the viewpoint of the narrator.
Vale,
Carolus Raeticus