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Family Sabellidal

collar, plate, body, length and ventral

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FAMILY SABELLIDAL Sabella alba a. sp.

Length 45 mm., of which the gills represent 10 mm. Body very slender, not more than 2 mm. in breadth at the collar.

Gills 17 pairs, colorless except for a fine longitudinal dusting of pigment along the bases of some of the rachises; bases of rachises connected by a very delicate membrane. On the outer surface of the rachises beyond the edge of the membrane are minute black ocelli, of varying number on different rachises and on different sides of the same rachis. These seem never to be more than 12 in a row. The extreme tip of each rachis is free from pinnules. The antennas are slender, sharp-pointed, with (in alcoholic material at least) a noticeable white longitudinal median line. On either side, ventrally, is a patch of fine dark-brown spots similar to those found on the bases of some rachises.

The collar is rather low, its ends widely separated dorsally, but nearly in contact on the ventral surface (plate 3, figs. 10 and 11). The ventral ends have a fine recurved tip, but elsewhere the edge is straight and not recurved. On either side is a ventro-lateral fissure, giving the collar a 4-lobed character.

Body colorless except for a series of dark-brown ventral shields on the somites. Throughout the greater part of its length these shields are divided by a deep, narrow longitudinal fissure. There are 8 thoracic somites.

Thoracic setae of two sorts, one (plate 3, fig. 12) lanceolate with asymmetrical expansion at the end, the other stouter, enlarged at the apex, shown in side view in plate 3, figure 13, and in full face in figure 14. The setae of the collar fascicle are lanceolate like those shown in figure 12. Uncinus of thorax with a single tooth and a definite crest of minute denticulations, but without second ary teeth (plate 3, fig. 15). The pennoned seta on the thorax have rather heavy stalks with very delicate, slender terminal portions. The tube is tough chitin, dark brown in color and very difficult to remove from alcoholic speci mens without injuring the specimen.

Type in American Museum of Natural History.

Collected in the Dry Tortugas in 1914 and at Guanica Bay, Porto Rico, in 1915.

ParasabeUs sulfurs& a. sp.

Length of body of type 65 mm., 18 mm. of which was in the length of gill.

The gills arise from a rounded basal portion as long as the first 4 body somites. There are about 15 on a side, of nearly uniform length, and with no inrolling on either edge. A very short portion of the apex of each rachis is free from pinnules. For a distance about equal to the length of the basal portion the rachises are united by a delicate web. Beginning justbeyond the web and extending to beyond the middle of the rachis each carries on either side of its outer surface a row of minute purple spots. The basal por tion of the gills is mostly of a purple color, while their greater part is sulphur yellow, though an occasional pinnule is purple, but these are too few to affect the general coloration. Tentacles slender, pointed, about twice as long as bagel portion of the gills.

A specimen collected in 1909 had, while living, a body bright yellow in color, with a greenish tinge dorsally and some purple markings on the dorsal surface of the collar In alcoholic material the body is colorless, except for the ventral shields, which are a grayish brown throughout.

Collar rather low, its dorsal ends widely separated (plate 3, fig. 16) while ventrally the ends are nearly in contact (plate 3, fig. 17). Each ventral end is prolonged into a triangular recurved lobe, and at the base of the lobe is a pad-like thickening of the collar. The whole collar is very inconspicuous and has a recurved edge.

The torus of the first somite is arranged obliquely just posterior to the dorsal free end of the collar on either side (plate 3, fig. 16). On the next 7 somites the torus is lateral and ventral to the seta tuft. Beginning with the ninth somite and extending throughout the remainder of the body the torus is dorsal to the seta tuft.

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