Check this vintage ad out...

Also pre- keeping fins and hands off bottom?

 

More information on the Scripps program: Connie Limbaugh got a great deal of information for the Scripps dive training program from the Navy UDT in Coronado.

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I still have one. The Desco Jack Browne mask was developed during World War II and never evolved very much. I had to train on it in the Navy but, thankfully, never had to use it after dive schools. It is the same mask shown in the Sea Hunt into.

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Here is an image of the demand version of the Jack Browne that came along in the 1950s but was even worse:

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Just to expand the point for other readers:
More than being at the forefront, the world's navies were the only source for reliable information on diving in the 1940s and early 50s. Definitely for documentation, unless you count Sir Robert H. Davis' Deep Diving and Submarine Operations: A Manual for Deep Sea Divers and Compressed Air Workers. Cousteau was in the French Navy and Hans Hass used Dräger rebreathers developed for the German Navy, though close variants were sold for mine safety and firefighting.

What passed for commercial diving before the 1960s could barely afford to replace their patched and leaking deep sea suits. What little they knew, or thought they knew, was more likely to be guarded as trade secrets than written down. The NEDU did a lot of basic research from the late 1920s on but the Royal EDU was not that far behind. A lot of Germany's research was conducted by Dräger, who was and is a huge medical equipment manufacturer.

There is a lot of information on the early evolution of diver training described in the Bev Morgan biography. Even the few commercial diving schools in the US of that era were started by ex-Navy divers.