The title is after the various paintings of Venus
floating in from the sea on top of half a scallop
shell, the most famous of which is Sandro Botticelli
's The Birth of Venus
"Trout" expanded slightly his original version, which appeared in the December 1974 and January 1975 issues of Fantasy and Science Fiction to include another fictional author, Jonathan Swift Somers III (fictionally a descendant of a third fictional author, Jonathan Swift Somers, who appears in Spoon River Anthology, by Edgar Lee Masters.) Somers III writes stories about Ralph von Wau Wau, a talking German shephard dog detective.
Much of the plot in Venus hinges on sex - in particular when the hero Simon Wagstaff becomes immortal, after drinking an elixir during a sexual liason with a feline female alien monarch who is "in heat". Possibly this reflects Trout's publishing strategy: in Kurt Vonnegut's novels, Trout finds it easiest to get published in pornographic magazines. There's also a distinct debt to Wilhelm Reich, especially towards the end of the novel, where some of Reich's wilder theories about orgone are given a slightly exaggerated fictional treatment.
The author actually went on to write stories by tertiary fictional author Jonathon Swift Somers III: A Scarletin Study, and The Doge Whose Barque Was Worse Than His Bight, both detailing the exploits of his talking dog detective Ralph von Wau Wau, were published in 1975 and 1976 repectively. But he never produced his projected short fictions The Wonder of the Wandering Wound, A Short Case of Longevity, The Caper of Kupper, the Copper's Keeper, The Case of the Stolen Dreams, The Adventure of the Tired Color Man, The Case of the Seeing Eye Man, The Hind of the Basker-bergs, The Shakedown of the Shook Sheik, The Four Musicians of Bremen, or the intended Somers III novel (also featuring Wau Wau) Some Humans Don't Stink.
Perhaps we should be grateful that the dog detective himself has (as far as we know) thus far refrained from writing any science fiction containing fictional science fiction writers.
Information from: http://users.castel.nl/~nuniz01/