For those interested in how BJJ developed from judo, I recommend Mastering Jujutsu
by Renzo Gracie and John Danaher.
One thing that hasn't been mentioned on this thread thus far is the fact that Mitsuyo Maeda (the fellow who brought judo/jujutsu to Brazil) also cross-trained and competed in English catch-as-catch-can (CACC)wrestling tournaments. CACC wrestling had both English (Lancashire) and American incarnations. As Danaher pointed out in Mastering Jujutsu
, there's even a famous old photo of Maeda in wrestling tights, performing a standard CACC control technique--a hammerlock/half-Nelson combo. The pic can be seen here: http://www.geocities.com/Colosseum/5389/maeda2.gif
There was a great deal of exchange in the late 1800s/early 1900s between Western wrestlers and Japanese judoka/jujutsuka. For example, the sub we now refer to as the heelhook entered the CACC syllabus as the "Japanese leglock", via early judo (before leglocks were banned, obviously).