CASTALIA FUSCA. 



127 



3. Castalia fusoa, Johnston, 1836. Plate XL VI, fig. 3 ; Plate LVIII, figs. 15 and 16— 

 head; Plate LXIX, fig. 16— foot; Plate LXXVIII, fig. 4— bristle. 



Specific Characters. — Head small, square, with two black eyes close together on each 

 side, the anterior elongated, placed obliquely, and with a cuticular lens. Tentacles, two, 

 slender ; palpi with a massive basal segment from which the short distal process passes off 

 at an angle. Tentacular cirri, two pairs, filiform, slightly segmented and of great length, 

 the dorsal being the longer. Body 1-3 inches long, scolopendriform, slightly narrowed 

 in front, and tapered to an attenuated tail with two long, slender anal cirri. Colour 

 pinkish or fawn, yellowish-brown, and purplish-pink, darker in the centre, with the dorsal 

 blood-vessel which makes a double curve behind the oesophageal region. Cirri pale. 

 Proboscis short, firm, cylindrical, the aperture surrounded by a dense fringe of filiform 

 papillse. Two thickened ventral edges (the "jaws" of Dr. Johnston). The body-wall 

 (Fig. 48) is as muscular as in G. punctata, though, perhaps, the ventral longitudinal 



Fig. 48. — Muscles of Castalia fusca, Johnst., as seen in section; n. c. nerve-cords cut in the 

 line of the ganglia. Other letters as before. 



muscles project less inferiorly. The strong oblique bands are attached to the firm summit 

 of the large nerve-area, which has externally hypoderm and cuticle. 



Feet prominent, longer than the diameter of the body ; biramous, for two small 

 spines pass to the base of the dorsal cirrus, which is very long and slightly tapered, with 

 a large and long ceratophore. Articulations are distinct towards the tip. The setigerous 

 (ventral) division is massive, with a blunt papilla for the spine, another a little above it, 

 and a third process is formed by the short ventral cirrus. Bristles leave the foot between 

 the posterior flap and the papillge in front, are yellowish, and boldly curved towards the 

 tip of the shaft, which is striated longitudinally and transversely. The end of the shaft 

 is not much dilated and is bevelled to a shoulder for the terminal blade which ends in a 

 curved claw with a secondary process beneath. The edge of the blade has minute 

 serrations at the base, then a series of larger curved teeth, followed by minute serrations 

 which diminish and disappear before the tip is reached. 



Synonyms. 

 1836. Psamathe fusca, Johnston. Loud. Mag. Nat. Hist., ix, p. 14, woodcut f. 1. 

 1840. „ „ idem. Ann. Nat. Hist., iv, p. 230, pi. vii, f. 4. 



