Note 21 — Chapter XII · ADAPTATIONS OF FISHES
Reading edition
See a more technical paper on this subject entitled "Relations of Temperature to Vertebræ among Fishes," published in the Proceedings of the United States National Museum for 1891, pp. 107-120. Still fuller details are given in a paper contained in the Wilder Quarter-Century Book, 1893. The substance is also included in Chapter VIII of foot-notes to Evolution: D. Appleton & Co.