In spite of looking like cryptic clues, these are in fact descriptions of creatures from the Dr. Seuss book On Beyond Zebra ("zoo/not enough"; homonym of "Geisel" in the title). The numbers are the letter of the creature's name to use, not the number of letters in the word. The animals are:
The indicated letters spell PART OF AN ACRONYM, which is a clue for the word INITIAL.