396 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
A very close relationship of jNIacroclinum to Amaroucium is not appar- 
ent to the writer. The areolation of the stomach does not exhibit the 
slightest indication of having arisen by the breaking up of a system of 
longitudinal folds such as is present in the stomach wall in that genus. 
Macroclinum pomum (Sars). 
Text-fig. 21; PI. 38, fig. S. 
1851. Amnroucium 'pomum Sars, Nyt Mag. Naturvidensk, vol. 6, p. 155. 
1859. Amaroucium pomum Sars. Forh. Videnskabs-Selsk. Christiania, p. 66. 
1863. Amarouciuin potuum Alder. Ann. Mag. Nat. Hist., ser. 3, vol. 11, pp. 
170, 171. 
1871. Macroclinum crater Verrill, Amer. Journ. Sci., ser. 3, vol. 1, p. 293, 
fig. 23-25. 
1872. Macroclinum crater Verrill, Amer. Journ. Sci., ser. 3, vol. 3, p. 212. 
1879. Macroclinum crater Verrill, Preliminary Check-list of Marine Inverte- 
brata, p. 27. 
1891. Macroclinum crater + Amaroucium poynum (?) Herdman, .lourn. 
Linn. Soc. London, Zool., vol. 23, p. 628 (listed among unrecognizable 
Polyclinidae. 
1893. ? Aplidiopsis pomum Herdman, Ann. Mag. Nat. Hist., ser. 6, vol. 12, 
p. 445. 
1896. Aplidiopsis pomum + Aplidiopsis sarsii Huitfeldt-Kaas, Norske Nord- 
havs-Exp., Zool, vol. 23, no. 1, pp. 13, 14, pi. 1, fig. 8-10. 
1903. Macroclinum crater + Macroclinum pomum Hartmeyer, in Romer and 
Schaudinn, Fauna Arctica, vol. 3, p. 319-322, text-fig. 37-39, pi. 
■ 6, fig. 5; pi. 13, figs. 6, 7. 
1904. Macroclinum pomum Hartmeyer, Wiss. Meeresunters., Abt. Helgoland, 
vol. 5. pt. 2. 
1905. Macroclinum pomum Bjerkan, Bergens Mus. Aarbog, no. 5, pp. 17, 18. 
1906. Macroclinum pomum Hartmeyer, Beitrage zur Meeresfauna von Helgo- 
land, in Wiss. Meeresunters., Abt. Helgoland, p. 126. 
1907. Macroclinum crater Redikorzew, Ann. Mus. Zool. Acad. Imp. Sci. St. 
P^tersbourg, vol. 11, pp. 148, 153. 
1908. Macroclinum pomum Bjerkan, Tromsoe Mus. Aarsheft., no. 25, p. 88. 
1909. Macroclinum pomum Hartmeyer, Bronn's Tier-reich, vol. 3, siippl., 
p. 1464. 
This species forms large rounded masses attached by a narrow area 
or raised on a very short thick peduncle. Often the surface exhibits 
large flattened or concave areas. The test in alcoholic specimens is 
tough, cartilaginous (especially the outer layer), and of a rather opaque 
yellowish or yellowish white color. The surface is rather smooth and 
often incrusted with a thin even la\er of sand grains, though in other 
