Your genus its worldwide, your spacest sublime!

Genus: A taxonomic category ranking below a family and above a species and generally consisting of a group of species exhibiting similar characteristics.

Spacest: species

Space: this and the reference to time in the next line refers back to the "space time" opposition associated with the Shem and Shaun characters, and also referred to prominently in the Mookse and the Gripes episode from earlier in the book.