14 SYDNEY J. HICKSON. 
There can be no doubt that this specimen belongs to the same species as those 
described by Kolliker (7) under the name Umbellula carpenteri. These specimens were 
five in number, and found by the ‘Challenger’ at depths of 1975 fathoms and 1950 
fathoms in the south polar seas; the stage of growth of the ‘ Discovery’ specimen 
being probably an older one than specimen E of the ‘ Challenger’ series. 
But although we may be satisfied to give the specimen Kolliker’s name, the careful 
description by Dr. Jungersen (6) of a series of specimens of the north polar and deep 
Atlantic species, U. encrinus, has impressed me with the belief that in time these two 
species (U. encrinus and U. carpenter’) will be merged into one. There is no doubt that 
they are closely related, but as accident has prevented me from further testing this 
opinion | must leave the problem for others to consider. The striking similarities in 
structure between these north and south polar forms of Umbellula is, however, a matter 
of theoretical interest. 
LIST OF MEMOIRS QUOTED IN THE TEXT. 
1. Gray, J. E. Catalogue of the Lithophytes in the British Museum, (1870). 
2. Hickson, 8. J. Trans. Zool. Soc. Lond., XIII., (1894), p. 338. 
3. Hickson, 8. J. ‘Southern Cross’ Collections, 1902, p. 293. 
4. Hickson, 8. J. Marine Investigations in 8. Africa, the Alcyonaria, Pt. II., (1904), p. 224. 
5. Hiles, I. Willey’s Zoological Results, Pt. I1., (1899), p. 196. 
6. Jungersen, H. F. E. Pennatulida, Danish Ingolf Expedition, Vol. V., (1904). 
7. Kolliker, A. Pennatulida, ‘ Challenger’ Reports, Vol. I., (1880). 
7A. Kolliker, A. Icones Histologic, 1864-5. 
. May, W. Hamburger Magalhaensische Sammelreise, Alcyonarien, (1899), p. 6. 
9. Roule, L. ‘Southern Cross’ Collections, 1902, p. 290. 
10. Studer, T. Monatsber. K. Akad. Wiss. Berlin, 1878, p. 662. 
11. Thomson, J. A., and Ritchie, J. Trans. Roy. Soc. Edin., XLI., (1906), p. 851. 
12. Valenciennes. Voyage sur la Vénus, 1846 (fig. only). 
13. Versluys, J. Siboga Expeditie, Mon. XTIIA., (1906). 
14. Wright, E. P., and Studer, Th. Alcyonaria, ‘ Challenger’ Reports, Vol. XX XI., (1889). 
¢ 
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DESCRIPTION OF THE PLATES. 
PLATE I. 
Fie. 1.—Umbellula carpenteri (reduced to d size). Au, Crown of Autozooids ; 0., Peduncular bulb. 
2.—U. carpenteri. Proximal view of crown of autozooids. Natural size. Si., Petaloid area of 
siphonozooids ; D., Dorsal petaloid area terminating in a large siphonozooid; V., Ventral 
petaloid area ; G., An autozooid that was injured, the tentacles missing. 
» 3—U. carpenteri. Distal view of the crown of autozooids. a, the ninth or “ Haupt” zooid. 
» 4.—U. carpenteri. Four siphonozooids of the petaloid areas. ent., the single long tentacle of each 
siphonozooid, x 40 diams. 
» 5.—U. carpenteri. Transverse section of one of the siphonozooids of a petaloid area, x 120. Si., 
Siphonoglyph ; d. m., Dorsal mesenteries. 
» 6.—U. carpenteri. Transverse section of a small siphonozooid of the peduncular bulb, x 120. 
» 7.—U.carpenteri. One of the tentacles of an autozooid, to show the arrangement of the pinn, x 23. 
» &.—Primnoella divergens. Two whorls as seen in a spirit specimen, showing the manner in which 
the scales project on the surface, x 10. 
5 9.—Primnoella divergens. A spicule of the calyx, x 50. 
» 10.—Primnoella divergens. A spicule of the coenenchym, x 50. 
a 
