"Ed [Ricketts'] reading was very broad. Of course he read greatly in his own field of marine invertebratology. But he read hugely otherwise."I enjoyed reading The log from the Sea of Cortez during my long flights to and from Turkey. Mine is a worn 1971 paperback I bought cheaply at the used bookstore a few years ago. It credits Steinbeck as the sole author, although many of the biological arguments and biophilosophical ruminations were probably Ed Ricketts' brainchildren. In fact, Chapter 14, March 24, Easter Sunday was an unpublished essay Ricketts had written and which I discussed here.
John Steinbeck, About Ed Ricketts, 1951, in The log from the Sea of Cortez by Steinbeck & Ricketts, 1941.
Invertebratology is the study of invertebrates. Steinbeck used it twice in his essay on Ricketts, but he probably wasn't the one who coined it. Otherwise, the word is not in common use; a Google search returned only 40 hits. Its unpopularity may be due to its length. "Invertebrate zoology" is also more descriptive.
By derivation, a person studying invertebrates would be an Invertebratologist.
Note added 27 October 2008: Deniz informed me that invertebratology is not in the Oxford English Dictionary.