. The Canadian field-naturalist. March, 1924] The Canadian Field-Naturalist 57 arranged with reference to the holes in the plate but as the plate develops it soon loses its sym- metry, one side usually developing more than the other, the knobs are more numerous, no longer regularly distributed, and connected with each other by crooked ridges. As the ridges become higher, knobs and low spinelets develop on them, and thus the rough outer surface of the plate is formed. In the pedicels the plates become more elongated, narrower and curved, the ridges and knobs are confined to the central part, an
. The Canadian field-naturalist. March, 1924] The Canadian Field-Naturalist 57 arranged with reference to the holes in the plate but as the plate develops it soon loses its sym- metry, one side usually developing more than the other, the knobs are more numerous, no longer regularly distributed, and connected with each other by crooked ridges. As the ridges become higher, knobs and low spinelets develop on them, and thus the rough outer surface of the plate is formed. In the pedicels the plates become more elongated, narrower and curved, the ridges and knobs are confined to the central part, and thus the supporting rods arise. Colour of preserved specimens, yellowish-white; tentacles darker. There is no clue as to what the colour in life may have been. There are 25 specimens of this little Cucumaria before me. All were taken in 10 fathoms, sand and mud, in Alert Bay, Queen Charlotte Sound, British Columbia, by G. M. Dawson, August 6, 1885. They were taken in company with lubrica, chronhjelmi, lissoplaca and populifera, and all five species were preserved together. It is hardly probable that the five actually live in such close relationship as this indicates. Probably field study in Alert Bay will show that each species has its own particular habitat. (Catalogue No. 594, Radiata, Victoria Memorial Museum, Ottawa. Cotypes.) Cucumaria vegae Theel. Theel, 1886, Challenger, Holos., p. 114. There are four little Cucumarias 10-20 mm. long which were taken in 10-20 fathoms, sand and gravel, at Discovery Passage, on the Vancouver Island side of Johnstone Strait, by G. M. Dawson in 1885. I have compared them with specimens of vegse from St. Paul's Island and find they are immature examples of that species. As yet only the largest has pedicels on the dorsal inter ambu- lacra and, in that case, the extra pedicels are all middorsal. Psolus chitonoides H. L. Clark H. L. Clark, 1902. Proc. Boston Soc. Nat. Hist., vol. 29, p. 335. There are two specimens of this holothurian from Ucl
Size: 2240px × 1116px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorottawafieldnaturalist, bookcentury1900, bookdecade1920
