These logos were designed by Dean Alejandro and submitted to the SeaMonkey Project for consideration in being used with their excellent internet software suite which is currently in development (it is based on the popular Mozilla Application Internet suite). The logo designs (along with other entries) can also be seen here. These designs are at rows 188-194.

Update: The Seamonkey council went with another design. Here is the announcement. These logo designs are therefore available for purchase.