Barrett mentions that, though the Meteorologica is a controverse work, much of which was probably not written by Aristotle himself, this first book is quite probably authentic; this view is augmented by the fact that it describes a comet of 341-340 BC which is also mentioned by other sources.
The relevant extract of Aristotle's work follows (see also the online version of the translation):
(II) Objections which apply to both those who hold this theory [that comets - or their tails - are reflections of some kind] and also to those who suppose comets are due to conjunction of two planets are (i) that some of the fixed stars have tails. And for this we need not rely only on the evidence of the Egyptians who say they have observed it; we have observed it also ourselves. For one of the stars in the thigh of the Dog had a tail, though a dim one: if you looked hard at it the light used to become dim, but to less intent glance it was brighter. (ii) Further, all the comets seen in our time disappeared without setting, gradually fading away in the sky above the horizon and leaving behind neither one star nor more than one. [..]
The first reference identifying Aristotle's "star with a faint tail" with M41 is from John Ellard Gore (1845-1910). While there is some probability for this identification, it is far from being safe; Barrett mentions that another candidate might be a train of stars near Delta Canis Majoris.
References
Last Modification: December 20, 2011