- Class Gastropoda (digitalatlasofancientlife.org)
Gastropods are the second largest class of animals (after the Insecta)—with 40,000–90,000 living species and at least 13,000 extant and fossil genera (Ponder and Lindberg, 2020)—and are also one of the most evolutionarily successful groups in the variety of ecosystems and habitats that they occupy.
- I remarked, moreover, with respect to experiments, that they become always more necessary the more one is advanced in knowledge; for, at the commencement, it is better to make use only of what is spontaneously presented to our senses, and of which we cannot remain ignorant, provided we bestow on it any reflection, however slight, than to concern ourselves about more uncommon and recondite phænomena: the reason of which is, that the more uncommon often only mislead us so long as the causes of the more ordinary are still unknown; and the circumstances upon which they depend are almost always so special and minute as to be highly difficult to detect.