Seta of first setigerous somite of two sorts; one with a long, slender shaft (plate 3, fig. 18), the apex bent and narrowed to an acute point, with an indi cation of a lateral wing on both the concave and convex sides of the bend: the second form is stouter, with the apex rounded and covered with spines and terminating in a short, slender point (plate 3, fig. 19).
Beta of later somites of four kinds. In the tuft about equal numbers of slender forms with curved apex, the bent portion covered with spines (plate 3, fig. 20) and of stouter forms with rounded ends (plate 3, fig. 21). In each torus is a single row of uncini, each with a single tooth and a long basal bar. Dorsal to the tooth are numerous fine surface striations, but no indication of secondary teeth (plate 3, fig. 22). In addition, below the uncini is a row of pennoned seta (plate 3, fig. 23).
Common in the Tortugas, living in a dark-brown chitinous tube, usually in holes in solid coral rock. The tube is usually much longer than the animal and apparently its secretion keeps pace with the deposition of the rock. in American Museum of Natural History.
I have included this in the genus Parasabella of Bush (1905, p. 191), distin guished from Sabella by the absence of a lateral incision in the collar lobe. In its general appearance and form of seta3 it resembles Protulides ekgans of Webster (1884, p. 325), but differs in the form of the collar.
Metalonome brumes a. sp.
Length of largest specimen, including gills, 30 mm. Length of gills, 10 mm. Diameter of thorax, 3 mm.
There are about 13 gills on a side, with relatively long pinnules, which have a wavy outline, giving the whole gill a feathery appearance. The antennas are short, broad at the base, with a very acute tip. The basal membrane of the gills extends for only a short distance up the plumule, and in alcoholic specimens this basal portion is a very dark brown, the color lightening very gradually toward the colorless apex.
Ends of collar widely separated on the dorsal surface, the dorso-lateral portions rather low, the edges not reflexed (plate 3, fig. 24). Ventral to the ventro-lateral notch the collar is produced on either side into a prominent pointed lobe (fig. 25), whose length is more than twice the width of collar. These lobes are in contact along the median line and cover a large part of the bases of the gills. Dorsal to them, between the bases of the gills, is as pair of lip-like folds, whose outer edges are in contact with and possibly are a pro longation of the ventral edges of the collar.
There are 12 thoracic seta-bearing somites. The first seta tuft is near the dorsal end of the collar, and there is no corresponding torus, while on the second and later seta-bearing somites there is a ventral torus. The torus becomes dorsal on the thirteenth setigerous somite. Ventral shields inconspicuous and divided longitudinally throughout the abdominal region by a narrow line.
The Bette of the collar fascicle are long, the terminal portion expanded laterally into a wing which is densely striated on its surface (plate 3, fig. 26, from a profile view). The thoracic Bette are in bundles, those of one aide of each bundle being similar in form to the collar seta, those on the other side having a terminal expansion ovoid when seen in face; between these two is a series graduating in form from one to the other; all have dense striations over the broadened surface. The uncini have a large tooth and a crest of 5 or 6 rows of smaller teeth (plate 3, fig. 27).
The tube is of thin white parchment covered at the end with fine white mud. Type and cotypes in the American Museum of Natural History.
The specimens were collected at Nassau, British West Indies, by Whitheld. I was unable to discover any pennoned Bette in the thorax of these forms, and consequently have included them in the genus Metalonome as defined by Bush (1905, p. 287).