got to agree with moonlighter and tatsblisters...nobody had herd the term longdog till the books came out and it is just splitting hares really ..
also wasn't the word lurcher ...derived from the term "to lurch" it just meant the dog used it's brain and cut corners on a course against a hare...something that crossbred greyhounds learnt to do by there owners who poached for food on a regular basis...rather than the sporting gent who kept pure greys for competitive coursing...
to my mind whether it's grey cross deerhound or collie it's still a lurcher