Note 536 — Chapter XI · THE LOGARITHMIC SPIRAL (continued 2)

The “lobes” and “saddles” which arise in this manner, and on whose arrangement the modern clas­si­fi­ca­tion of the nautiloid and ammonitoid shells largely depends, were first recognised and named by Leopold von Buch, Ann. Sci. Nat. XXVII, XXVIII, 1829.