SQL Server 2008 :: Transactional Replication Snapshot In Multiple Files

We have a large database with a small number of large tables in it (and a larger number of SMALLER tables), and it is a publisher for a transactional replication scenario. When I create a snapshot to initialize a new subscription, I notice with the larger tables that sometimes it generates multiple files in the snapshot folder, usually in multiples of 16, and numbers them like this:

MyTable_3#1.bcp
MyTable_3#2.bcp
...
MyTable_3#16.bcp

With other tables, I'll get just one LARGE snapshot file, named:

MyOtherTable_4.bcp

In the latter case, the file can be very large (most recent is 38GB).

In both cases, the subscription will eventually be initialized, but the smaller files will generate separate log entries every few minutes in the Replication Monitor, showing 'Bulk Copied data into 'MyTable' (34231221 rows)', whereas the larger table will generate only ONE log entry, showing 'Bulk coping data into table 'MyOtherTable', and it may take a couple of hours before there is anything else showing...except for an entry saying, 'The process is running and is waiting for a response from the server.'

My question is: what would be the difference between the two tables that would result in one generating MULTIPLE snapshot files, the other only a single, much larger one? The only difference I can see in the table definition is that the one generating multiple files has a clustered index, whereas the others do not.