During this voyage notes of the habitats of considerably more than a thousand species of Mollusca and Echinodermata were carefully registered.
"Voyage Of H.M.S. Rattlesnake, Vol. 2 (of 2)" by John MacGillivray
Still more striking cases could be given with respect to the Echinodermata.
"The Variation of Animals and Plants Under Domestication, Volume II (of 2)" by Charles Darwin
In Echinodermata a certain amount of mesenchyme appears before the epithelial mesoderm, which is formed later as gut-diverticula.
"Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 3" by Various
ECHINODERMATA, absence of secondary sexual characters in, i.
"The Descent of Man and Selection in Relation to Sex" by Charles Darwin
Echinodermata, 33, 43, 44, 122.
"Stories of the Universe: Animal Life" by B. Lindsay
Echinodermata, 108; classification of, 120.
"Elementary Zoology, Second Edition" by Vernon L. Kellogg