[64] "All the component cells of any one organism may be considered as the descendants of the primordial cell in which it originated." (Dr. Carpenter; Comp. Physiol.; p. 396. 4th Ed.)
[65] I conclude so; because I have kept specimens of Echinus, not full grown, in healthy condition, for nearly a year, without any perceptible increase in their dimensions.
[66] I am not aware that this stage of the Entozoon has been actually observed; but from what we know of its previous and subsequent history, the correctness of the statement in the text will scarcely be disputed. (See Prof. Owen: Comp. Anat. of Inverteb. Ed. 2. p. 74.)
[67] See Notes to "Marmion."
[68] Report on Brit. Annelida, p. 194.
[69] We have no direct observations, that I am aware of, on the larval state of the African Goliathi; but their near ally, the Cetonia aurata of Europe, passes four years in the grub condition, as does also the Melolontha vulgaris, another lamellicorn beetle. The Lucanus cervus, or Stag-beetle, continues a larva for six years.
[70] Fabre; Ann. d. Sci. Nat.; iii. 1855.
[71] B. splendida, has been ascertained to have existed, as an inmate of the wood of a table, for more than twenty years. (Linn. Trans.; x. 399.)
[72] The rate of increase in dimensions shown by specimens of this species, now so frequently kept in Aquaria, warrants this assertion; though how many years a Crab takes to attain adult size, no exact observations, so far as I know, testify.
[73] The exuvia of the cirri are sloughed from the Balanidæ about every week in summer; and perhaps this process is coetaneous with an addition to the valves.