while i agree with john conway that tonsoidal torus is likely a misprint of some kind, the OED does suggest some sort of meaning. (don't mind if some of the text below prints funny on your system; our system uses a different character set.)
the first idea is the verb tons, which is derived from the verb to shear or clip; it can mean either cut hair, or dress up (1828 Craven Gloss., Tonse, to dress, to deck, to trim. Tonsed, dressed up. `Thou's finely tonsed this morning.)
the second idea is tonsil, which has the normal meaning (gland in the throat) but can also mean any two lobed structure, e.g. 2. Each of the two lobes of the cerebellum; also called amygdala. 1891 in Cent. Dict. 1899 in Syd. Soc. Lex.
the third idea is tonsile: That may be clipped or shorn. 1664 Evelyn Sylva (1776) 321 The Shrub [Juniper] is tonsile and may be shorn into any form. 1707 Mortimer Husb. (1721) II. 366 In mild Weather, clip Phillyrea and other tonsil Shrubs. 1791 Gilpin Forest Scenery i. 93 The yew is of all other trees the most tonsile. 1847ÃÂ¢ÃÂÃÂ78 Halliwell, Tonsile-hedge, a hedge cut neat and smooth. North.
finally, tonsure, while normally meaning the clipping or shaving of teh head, can also refer to clipping a coin or hedge: The clipping
(a) of coin;
(b) of shrubs or hedges. Obs. rare. 1621 Bolton Stat. Irel. 12 (Act 25 Hen. VI) Ireland is greatly impoverished..by the..carriage..into England of the silver plate, broken silver Bullion and wedges of silver made of the great Tonsure of the money. 1691 in ArchÃÂÃÂ¦ologia (1796) XII. 185 His yew hedges with trees of the same..kept in pretty shapes with tonsure. Ibid. 186 A fair gravel walk betwixt two yew hedges with rounds and spires of the same, all under smooth tonsure.
well, what this all means is beyond me, but my guess is that tonsoidal torus refers to a torus that has been trimmed down from a doughnot shape, and if the word was chosen really carefully, it was trimmed down to a twin-lobed shape.