Harold Corwin

IC 3319 is perhaps = NGC 4390 = IC 3320. Found by Schwassmann on his 6-inch plate of the Virgo Cluster area, this does not exist -- or is identical with IC 3320 = NGC 4390. Though there is a faint star less than an arcminute west-southwest of Schwassmann's position, this does not match his description which is identical to that for NGC 4390 (which Schwassmann did not name as the NGC object, by the way). Is it possible that he made an error in his measurement reductions for the IC objects? They occur in different declination zones in his list, so this is a possibility.

― IC Notes by Harold Corwin

Courtney Seligman

Per Dreyer, IC 3319 (Schwassmann #140, 1860 RA 12 18 44, NPD 78 50.0) is "pretty faint, pretty small". The position precesses to RA 12 25 50.8, Dec +10 23 27, but there is nothing there save for NGC 4390, which lies 4 arcmin to the north. Such a large error would be unusual for Schwassmann, so this probably represents a nonexistent object; but per Corwin Schwassmann may have made a reduction error in an otherwise identical observation of his #155, so there is a possibility that it is a duplicate of IC 3320 (on the basis of its nearly identical description). In either case this IC entry would serve no useful purpose, so it is usually ignored.

― Courtney Seligman, Celestial Atlas