(1) As in §g we have here a departure from the common version, which makes the mother of Thomas ap Llywelyn to have been 'Elenor verch arglwydd Barre,' (Pen. 127 pp. 31, 39, 71). In another place, however, Ieuan Brechfa says: Mam Tomas ap Llywelyn oedd verch Syr Robertt y Val, arglwydd Trefgarn Ywain, yr honn dref a gafas henw gann Ywain ap Llywelyn, brawd Tomas ap Llywelyn, yr hwnn Ywain a vu varw yn ddietifedd, ar arglwyddiaeth a gwy[m]podd y Domas ap Llywelyn. (Pen. 131 p. 257). (m) The mother of Margied ferch Tomas has already been given in § g. The correction given here was inserted by Robert Vaughan in A. This Margred (or Elen) ferch Maredudd was the wife of Gruffudd ap Ieuan ap Gruffudd ap Dafydd of Iscerdin. (Pen. 131 p. 257, Dwnn i. 27, ii, 30). This section and the next are entirely out of place here. (n) Ell-liw is the regular spelling by Ieuan Brechfa of this name which appears earlier as Ellelw or Ellylw and later as Elliw or Ellyw. Achoedd gwyr Dyfed does not appear in Pen. 131 and is evidently lost. But the continuation of the pedigree is given by leuan Brechfa on p. 305. See PP § 64(2). ABBREVIATIONS ABT 'Achau Brenhinoedd a Thywysogion Cymru' by P. C. Bartrum, Bulletin of the Board of Celtic Studies, University of Wales, xix, 201-225. Dwnn Heraldic Visitations of Wales by Lewis Dwnn, edited by Sir S. R. Meyrick, 2 vols., Llandovery, 1846. Harl. Harleian MS. HL 'Hen Lwythau Gwynedd a'r Mars' by P. C. Bartrum, National Library of Wales Journal, XII pp. 201-235. PAR 'Plant yr Arglwydd Rhys' by P. C. Bartrum, National Library of Wales Journal, XIV pp. 97-104. Pen. Peniarth MS. PP 'Pedigrees of the Welsh Tribal Patriarchs' by P. C. Bartrum, National Library of Wales Journal, XIII pp. 93-146. P. C. BARTRUM Berkhamsted