Schneider Angulon is 6/2 more like the ortho protar than a Dagor.
Kingslake called the Angulon a reversed Dagor, Flügge lists it as a "Satzanastigmat", Brandt describes it as modified Gauss 2nd type design, and above it's related to the Ortho-Protar which in turn could be regarded as a devirative ot the "Protorlinse"/"Doppelamatar" decribed in D.R.P. 196734a - whereby one would re-approach the Dagor.
One can be grateful that most lenses produce clearer pictures than the many attempts to put lens designs in genealogical order. As lenses don't inherit genetic codes it is IMO rather doubtful to sort them into groups, types or families or in genera and species as if one could build up a Linnaeus system of lenses. Merely comparing obvious similitarities ( and forgetting to look at the glass combinations that decide whether a cemented surface will be collective or diffractive ) can easily lead to putting lenses into cuckoo nests.
A. H. Tronnier, the Angulon's designer, explicitely stated in his patent application (D.R.P. 579788, 1930) that his invention "refers to a modification of spherically, chromatically and astigmatically corrected double-lenses - 'Doppelobjektive' - that are made of two groups of cemented triplets whose single elements present three concave surfaces towards the diaghragm, and of which the two hollow surfaces next to the stop act as diffracting, whereas the third concave surface and the convex cemented surface [both as seen from the stop] have collecting power".
I imagine there are by far too many lenses having those characteristics to reasonably say this one or that one should be tagged as Angulon's father or grandmother.
