. Bulletin - United States National Museum. Science. ASCIDIANS OF THE PHILIPPINES VAN NAME. 149 of the object on which it grew, not to any difference of species. Color usually chalky or yellowish white. In specimens from two stations (D5139 and D5154) the upper or free surface of the colony is somewhat mottled with a blackish pigment. The branchial aper- tures of the zooids appear in the contracted preserved specimens as minute depressions, and in some specimens are quite conspicu- ous. Common cloacal apertures are only occasionally recognizable, but are apparently generally rather numerously
. Bulletin - United States National Museum. Science. ASCIDIANS OF THE PHILIPPINES VAN NAME. 149 of the object on which it grew, not to any difference of species. Color usually chalky or yellowish white. In specimens from two stations (D5139 and D5154) the upper or free surface of the colony is somewhat mottled with a blackish pigment. The branchial aper- tures of the zooids appear in the contracted preserved specimens as minute depressions, and in some specimens are quite conspicu- ous. Common cloacal apertures are only occasionally recognizable, but are apparently generally rather numerously distributed over the surface. Spicules are abundant in most parts of the colonies, often to an extent rendering the test hard and brittle. The spicules are mostly considerably larger than in Didemnum ternatanum, well developed ones averaging to mm. in diameter, or in some colonies larger ( to mm.). They are stellate; their rays rather few and long, regularly tapering in some. 101 lor Figs. 98-101.—Didemnum grande (Herdman). 98, Typical spicule. X 700. 99, Common forms op spicules. X 700. 100, Zooid. X 32. 101, Spicules from COLONY FROM STATION D5145. X 700. colonies, in others usually more nearly cylindrical and truncated at the tip (figs. 98 and 99). Zooids greatly contracted in nearly all the specimens so that the determination of their structure is difficult. In their contracted and preserved state they often do not exceed 1 mm. in length; they are numerous and closely placed in the colony. Branchial aperture with 6 small lobes; atrial aperture neither produced into a tube nor provided with a languet. Mantle musculature mainly longitudinal, forming distinct bands on the thorax. A muscular process extending into the test from the constricted middle portion of the body is present. Dorsal languets apparently arising from the transverse vessels a little way to the left of the median dorsal vessel. Stigmata in four rows, rather few in number; in one zooid 9
Size: 2424px × 1031px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorun, bookcentury1800, bookdecade1870, booksubjectscience
