. Bulletin - United States National Museum. Science. 134 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. them through vascular processes arising from the posterior end of the abdomen and joining the common stolons. The smaller specimen is a looser group of a few zooids connected by stolons. The largest zooids are in the preserved condition about 23 mm. long. Each consists of a long, very narrow abdomen inclosed in a tubular sheath of tough test which extends posteriorly into a more or less elongate pedicel and at the anterior end enlarges (expanding more toward the ventral than toward the dorsal
. Bulletin - United States National Museum. Science. 134 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. them through vascular processes arising from the posterior end of the abdomen and joining the common stolons. The smaller specimen is a looser group of a few zooids connected by stolons. The largest zooids are in the preserved condition about 23 mm. long. Each consists of a long, very narrow abdomen inclosed in a tubular sheath of tough test which extends posteriorly into a more or less elongate pedicel and at the anterior end enlarges (expanding more toward the ventral than toward the dorsal side) into a rounded or oval mass inclosing the thorax. The thorax is short, wide in a dorso-ventral direction, and narrow from side to side. Branchial aperture slightly lobed or almost plain, atrial aperture larger, and plain edged. Neither is greatly produced. The abdo- men joins the thorax at the extreme posterior dorsal part of the latter, and an abrupt bend in the proximal part of the abdomen is generally present, so that the main axis of the thorax as- sumes a direction nearly at right angles to the long axis of the abdomen and pedicel. Mantle thin; about the apertures there are slender circular fibers, but no strong sphincters. On each side of the thorax about 15 narrow widely separated muscle bands extend poste- riorly from the region about and between the apertures, each being generally formed by the union of two or more slender bands. Trans- verse muscles are but little developed, though a few slender circular bands cross the longitudinal ones on the anterior part of the thorax. Tentacles 16; 8 large and 8 smaller ones alter- nating. Dorsal tubercle prominent; cup-shaped with a rounded orifice. Dorsal lamina replaced by a series of large triangular languets borne transversely upon the wide median dorsal vessel. They are continuous at their lateral angles with broad membranes borne along the whole length of the transverse vessels of the sac. Stigmata long and narrow, s
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Keywords: ., bookauthorun, bookcentury1800, bookdecade1870, booksubjectscience
