VAN NAME: COMPOUND ASCIDIANS. 
391 
1872. Lissoclinum aureum Verrill, Amer. Joura. Sci., ser. 3, vol. 3, p. 212. 
1879. Lissoclinum aureum Verrill, Preliminary Check-list of Marine Inverte- 
brata, p. 27. 
1891. Lissoclinum aureum Herdman, Journ. Linn. Soc. London, Zool., vol. 
23, p. 629 (listed as uncertain species). 
1909. Lissoclinum aureum Hartmeyer, Bronn's Tier-reich, voi. 3, suppl., pp. 
1453, 145G (listed as uncertain species). 
The colony is of more or less irregular outline, flat and incrusting, 
or more usually somewhat convex above, with thick rounded edges. 
The largest specimens do not much exceed 30 mm. in greatest diameter; 
3 to 6 mm. is the usual thickness, but this may be exceeded in some 
parts of the colony in the case of large specimens. According to 
Professor Verrill (1871a), the color in life is light yellow with bright 
orange zooids. In alcoholic 
specimens the test is grayish, 
and often transparent enough to 
allow the zooids to be distinctly 
seen. The latter are numerous 
and apparently arranged in sys- 
tems of considerable complexity. 
The test contains large oval cells. 
The extent of the development 
of cavities in the common test is 
very variable in this species. In 
some colonies (including many 
of those in which spicules are 
]>ractically or entirely wanting, as well as those with many spicules) 
they are well developed, the test in the interior of the colony being 
reduced to a thin tough capsule surrounding each zooid; in others 
they are apparently entirely wanting, and the test substance is as solid 
and continuous as in a Didenmum. 
Professor Verrill mentions no calcareous spicules. Nevertheless a 
few at least may be found in many colonies by a careful microscopical 
examination. Not only are they generally insignificant in number, 
but most of them are far from regular in form, a considerable part 
being better described as irregular or more or less crystalline deposits 
of calcareous matter, while the regular ones are of spherical or stellate 
form, often 0.03 mm. to 0.05 mm. in diameter, and are provided with 
numerous but short and frequently somewhat notched or broken 
Text-tig. 18. — Lissoclinum aureum Verrill. 
Spicules. X 515. This figure and fig. 19 
are from different colonies. 
