1911.] NATURAL SCIENCES OF PHILADELPHIA. 295 



All three examples have a diameter of about 1 mm. Prostomium 

 relatively smaller and more slender than usual in the genus. Eyes 

 apparently wanting, but a small median brown spot on the dorsum of 

 the prostomium immediately beneath the border of the nuchal fold. 

 Parapodia poorly preserved, but evidently small and inconspicuous, 

 and evidently with the lips little produced, though the postsetal is 

 somewhat the longer. Most interesting are the setae. From somite 

 III to XXV all setae are of the capillary bilimbate type. A few 

 segments beyond XXV crochets appear and continue to the end of the 

 pieces or beyond C. On anterior segments the limbate setae agree 

 with Tread well's description, being long and slender, bilimbate and 

 bent. They number ten or twelve and the ventral four or five are 

 longer than the others. Farther caudad, after the crochets appear, 

 the number of limbate setae is reduced to a single short one dorsal to 

 the crochets and five to six ventral to them in subacicular bundle. 

 It is the latter that become so greatly elongated, projecting far beyond 

 the ends of the parapodia and in one specimen equalling the diameter 

 of the body. They are nearly straight with greatly restricted limbae 

 and the shaft continued into an excessively tenuous end. Anteriorly 

 the crochets are restricted to two in t the supra-acicular fascicle, but 

 farther back two more are added in the subacicular fascicle. They 

 are little, if any, stouter than the setae, anteriorly margined for a short 

 distance below the small head. Within a few segments, however, 

 they lose the margin and assume the form figured by Tread well. 



While the jaws in general resemble Tread well's figure, there are some 

 differences which it seems probable result from imperfections in 

 Treadwell's specimen. The maxillae are remarkably massive for so 

 small a species. Forceps jaws characterized by the very small base; 

 maxillae II with five teeth on the right and four on the left side, the 

 first tooth on each side being very large and well-separated from the 

 others by a wide internal. The anterior pairs of plates (III) are both 

 very large, triangular and bear a single apical tooth. Mandibles pale 

 with dark tips and differing little in form from those of L. bifilaris. 



Station 4,390, off Santa Catalina Islands, 33° 02' 15" N., 120° 42' W., 

 1,350-2,182 fathoms, gray mud and fine sand. 



Aracoda gemimaculata sp. nov. PI. XX, figs. 143-149. 



Form slender, subterete, but owing to the prominence of the para- 

 podia appearing widened and depressed in the middle and posterior 

 regions. The type, in which the caudal end terminates in a small 

 cone of regeneration, is 165 mm. long and 2.8 mm. wide, exclusive of the 

 parapodia. Segments 278. Four other examples accompany the 



