LEPTOECIA ABYSSORUM. 321 



The peristomium is decidedly wider than the prostomiuni and is very much 

 (nearly one and two thirds times) longer. The anterior margin above is straight, 

 or nearly so. Laterally it curves forward and embraces the sides of the pro- 

 stomiuni. The lower lip consists of a rather small, more elevated, subtriangular 

 area set off on each side by a depression extending mesocaudad from the anterior 

 margin. Its anterior border protrudes forward and the edge is straight. (Plate 

 36, fig. 1, 2). 



The second somite (first metastomial) consists of a wider anterior division, 

 from which the parapodia arise, and a narrower caudal ring ; its total length is 

 about equal to that of the peristomium. The succeeding somites decrease 

 gradually in length to the fifth, which is four fifths as long as the peristomium 

 or as the second somite (first metastomial), the followmg segments through 

 the middle region running of the same length, or nearly so. In the posterior 

 region they become much shorter, only half as long as the fifth, etc., and m the 

 narrowed caudal division only a third or fourth as long. The somites are dor- 

 sally moderately arched, ventrally more nearly flat, the body being compressed 

 dorsoventrally, and in the type mostly strongly so at the caudal end. 



The first parapodia are attached laterally at the anterior border and 

 nearer the ventral surface of the somite; they extend directly forwards or but 

 very slightly ectad and close to the side of the peristomium; they are cylindrical 

 and long, attaining, or very nearly attaining, the anterior end of the peristomium. 

 The notocirrus is attached dorsally a little distad of the middle; it is slender, 

 moderately tapering, and short, not extendhig beyond the distal end of the 

 parapodiiun. The neurocirnis is attached on the ventral surface farther toward 

 the base; it is slender and short, not extending beyond the beginning of the 

 distal third of the parapodium. The parapodium at the distal end presents 

 only a slight presetal elevation; Ijut caudad of the setae there is a prominent, 

 wide, distally widely rounded or subtruncate, postsetal lobe. (Plate 37, fig. 1). 

 The second parapodia are abruptly very different; they are similarly attached 

 at the anterior end but extend more ectad and are very much shorter. Theh 

 notocirrus is of a similar form and size but is attached proportionately decidedly 

 farther proximad. The neurocirrus is attached at the veiy base and is proxi- 

 mally stouter than that of the first parapodia. The postsetal process is more 

 slender, strictly cirriform, and is much longer than in the first foot. (Plate 37, 

 fig. 2). The tliird parapodia are attached in the same manner as the second ones, 

 have a similar dkection, and are of essentially the same size. The noto- 

 cirrus and the postsetal process are the same in form, size, and position; but the 



