My reading of LC's Catalog of Copyright Entries, Motion Pictures,
1912-1939 suggests that the Disney cartoons were released as discrete
items and not as a series. The index indicates that Looney Tunes was a
series.
 
I note as well that cartoons were registered in the names of Disney
(Walt) Enterprises, Disney (Walt) Productions, Disney (Walt)
Productions, Inc., Disney (Walt) Productions Ltd., and Disney, Walter E.
---Yet more reasons to appreciate careful bibliographers.
 
-Henry Breitrose
 Dept. of Communication
 Stanford