STAUEOCEPHALUS PALLIDUS. 363 



and the absence of serrations. The great length, straightness, and slenderness of the 

 dorsal bristles may be connected with a sexual change associated with the largely 

 developed ova. 



The example is a female laden with large ova, each of which has its longer diameter 

 exceeding the vertical diameter of the foot. 



Unfortunately the head and anterior region were injured, so that considerable doubt 

 must remain. It differs from Staurocephahis pallidus, Langerhans, in the presence of 

 four eyes, and in the structure of the bristles. 



4. Staubooephai/us pallidtjs, Langerhans, 1879. Plate LXXXVII, fig. 9— head, 

 9 a— foot; Plate LXXXVI, figs. 10, 10 a, and 10 b— bristles. 



Specific Characters. — Head with only two eyes ; tentacles nine to ten, ringed, and 

 longer than the two-jointed palpi. No nuchal grooves. Body 1 cm. long, with fifty 

 segments. First two without feet and third without a dorsal cirrus. Anal segment with 

 two longer jointed dorsal and two smaller simple ventral cirri. Lower jaw with from seven 

 to ten teeth on either side, and three to five free denticles. Upper jaw as in other species, 

 only with two rows of teeth without accessory jaws. The plate of the upper row has 

 about twenty-five teeth, simple in front but posteriorly denticulated. That of the lower jaw 

 is a thin toothed leaf, having smooth upper but denticulated lower teeth. Foot as long as 

 breadth of body ; dorsal bristles simple, serrated, or with a distal process ; in the fourth 

 segment simple, serrated; twelfth segment with long simple tips above the serrated edge ; 

 in the thirteenth segment stout bifid forms. Inferior division has compound bristles, the 

 terminal process having a hook distally and a process beneath (Langerhans). 



Synonyms. 

 1879. Staurocephalus pallidum, Langerhans. Zeitschr. f . wiss. Zool., Bd. xxxiii, p. 300, Taf . xvi, f . 35. 

 1904. „ „ Allen. Journ. M. B. A., n.s., vol. viii, p. 226. 



Habitat. — Dredged on Asia shore, Plymouth (Allen). 



Head (Plate LXXXVII, fig. 9) with only two eyes ; tentacles with nine double rings, 

 longer than the bi-articulate palpi. No nuchal grooves observed. 



Body about 1 cm. in length (Langerhans), and having fifty-nine segments. The first 

 two segments are devoid of bristles, and the third has no dorsal cirrus, which, as a two- 

 jointed structure, appears on the fourth. Anal segment with four cirri, two longer jointed 

 dorsal cirri, and two smaller simple cirri ventrally. 



Lower jaws armed with seven to ten teeth on either side, and three to five denticles. 

 Upper jaw as in other species, only with two rows of teeth, without secondary jaws. 

 The plate of the upper row is compact, with about twenty-five teeth which are more 

 simple in front, but posteriorly denticulated. The plate of the lower jaw is a thin, 

 toothed leaf, with smooth teeth in the upper but denticulated teeth in the lower row. 



Foot as long as the breadth of the body, with the bristles of the upper row simple, or 

 with a distal process and serrated edge beneath ; in the fourth segment simple, serrated ; 

 at the twelfth segment with long simple tips above the serrated region ; at the thirteenth 

 segment the bristle is bifid, with a few serrations on the curved limb. In the inferior 



