Versions Of Mars

In James Blish's Cities In Flight, Volume I, They Shall Have Stars, and in the second of Blish's two Jack Loftus novels, Mission To The Heart Stars, the long extinct Martians had covered their planetary surface with the Diagram of Power.

In Blish's first Haertel Scholium novel, Welcome To Mars, Martian canals are crustal faults or spalled cracks caused by meteor impacts and the intelligent six-foot-long dune-cats had been domesticated by the just-extinct Old Martians whereas, in "No Jokes on Mars," the four-foot-long but otherwise identical dune cats (unhyphenated) are possibly descended from the long-extinct Canal Masons.

In After Such Knowledge, Volume III, A Case Of Conscience, there are unintelligent Martian sand crabs.

The "Diagram of Power" Mars exists in two timelines, those of Cities In Flight and of the Loftus novels.

Although Blish stated that "No Jokes on Mars" was set at least a decade later than Welcome To Mars, it is clear that the story and the novel are set on similar but different versions of Mars and therefore in different timelines.

Neither version of the dune-cats exists on the "Diagram of Power" Mars but the sand crabs might although there is no reason to think that they do.