Pap Boats (aka: pap boats, pap cups, feeding boats and/or medicine cups)
One quickly realizes that pap boats come in many strange and unusual shapes and sizes. One general theme, though there are even exceptions to this, is that pap boats are around 4 inches in length, generally are without a handle, and are often confused with small creamers or sauce boats. In fact a couple of the examples above I could easily find listed today somewhere on the web as being described as both a "pap boat" and a "sauce boat" if I really tried. One rule of thumb I have used in my determination is that "if" it could have been used as a pap boat and it is around 4 inches in length it might be a pap boat (or other type of feeder).
Regarding the question what is "pap". I have seen many descriptions (recipes) and they all seem to have the same common elements. In its simplist form it was a mixture of bread, flour and water. As one can imagine it often was somewhat lumpy so that is why most pap boats had open tops (or at a minimum somewhat larger than usual spout openings) so that the contents could move easily when being fed. There were also variations that involved adding milk and butter to the mixture (instead of water) and this was called "panada" I recall. While I could go on and describe other variations and mixtures you can hopefully get the picture that these boats had an important use once upon a time.
Please look at the Photo Library as it contains an extremely large inventory of wonderfully representative samples to enjoy and study.