IMP XXXXII COS XVII P P (type III / II, B, 2 dots on reverse) (441 / 450)
Bust of Theodosius II facing, cuirassed, wearing a helmet with crest and a pearl diadem. Holding a spear passing behind his head with the right hand and a decorated shield with a horseman slaying an enemy, with the left hand.
PP Constantinople seated left on a throne, holding a spear with the left hand and a globe surmounted by a cross with the right hand. A shield behind the throne and a star in the field to the left.
Marks
Photo of a coin sold on 24/11/2008 by Numismatik Lanz München, Auction 144, lot 740, link to the sale: https://www.acsearch.info/search.html?id=551818, link to their website: http://www.numislanz.de/. It is the copy quoted in the RIC X n°320, from the sale: Numismatica Ars Classica, Zürich, Auction A, 27 and 28 February 1991, lot 2042.
Variant without a dot on the obverse and two dots on the reverse located after XVII and the first P of P P. COMOB mark. Reverse of type III (legend with dots) and design of type II, shield of type B.
The ranking follows the positional order of the dots on the reverse (before the first or second... abbreviation or date), This is the reason why this coin is classified first ahead of coins without officina letters, which are themselves grouped among other coins with officina letters. Each difference in the position of the dots is classified as "var" if the same "var" exists with two different officina letters, So the first one will be classified as "var" and the second coin as "var, a" with the small "a" indicating the next officina letter. Thus we have, for example, the AYC #39 var with the officina 
and the AYC #39 var, a with the officina S, the two numbers having exactly the same dots positions in the legend.
Die break on the obverse near "F AVG," further suggesting the likely reuse of old dies for this series with dots especially since this die reminds me of another coin without dot on the reverse. Same die? That remains to be verified.
On many coins (regardless of the number of dots), there is a sort of dark dot located between the two Ps or after the last one (like on this coin referenced here). If one of the dots is unmistakably present after one of the Ps, the other letter often shows another dark dot. Is it a case of a clogged die revealing a tiny remnant that looks like a sort of smudge due to the lighting in the photo? This also applies to other spots in front of other letters (though this is less common). It could just as well be a matter of micro-cracks in the die like those seen on the obverse but the location of these small details on the reverse is peculiar, as they are situated between the letters.
Type III: with the mark CONOB or COMOB (CONOB here). Legend punctuation on the reverse. This corresponds to type II of RIC X. Variant A and B are the same as RIC X: A = large, B = smaller, rounder shield. This type blends characteristics of types I and II in terms of design and the position of the legend relative to the shield: Constantinople large or small, helmet flat or not, drapery tight or not natural, legend ending before or at the level of the shield. The likely reuse of old reverse dies (there are already links between obverse dies and coins without reverse dots) consequently mixes the first two types. This mixing of the two types may also demonstrate the high probability that this series with dots on reverse is the last. For each Type III coin, I add the reverse design type after ''/'', thus giving either: ''III / I'' or ''III / II'', designating a Type III reverse with a Type I or II design followed by shield type A or B.