UML Aggregation with and without arrow head

Question

I always thought that the UML aggregate is defined as a black (filled) diamond at the beginning of a path and no arrow head that the end:

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Answer 1

An association has two ends. An association’s end is modeled by means of a UML Property which can be owned by the classifier involved at the related end of the association, in that case the association is said to be navigable as the source classifier can directly refer to the target instance (the instance at the other end of the association) by means of that property. Otherwise the property representing the association end may be owned by the association instance itself

see http://lowcoupling.com/post/47802411601/uml-diagrams-and-models-with-papyrus