NO. O NEW rOLYCHAETOUS ANNELIDS TREADWELL 9 



on to the lateral regions. The posterior margin is prominent and is 

 continued forward on either side nearly to the middle of the plate. 

 Between these two portions is a thin memhrane drawn out on the 

 right side into three, and on the left into four, sharp-pointed processes. 

 The surface of the cephalic plate is deeply hollowed just in front of 

 the posterior margin and more shallow elsewhere. The median ridge 

 extends only about half the length of the plate and has a cone-shaped 

 outline. Its dorsal surface is marked by transverse lines. 



A prominent collar on the anterior margin of the first setigerous 

 somite overlaps the posterior margin of the buccal somite for its 

 entire circumference. The anal funnel (fig. 23), has a prominent 

 bilobed dorsal and a single ventral lip. On the margin of the dorsal 

 lip are a few slender cirri. The first four setigerous somites are short, 

 the next five longer, anct the final ones shorter again. 



There are two- kinds of setae. The first are slender and sharp- 

 pointed, arranged in tufts in which there is great variation as to 

 length. Some are very short, others several times as long. Some at 

 least, and probably all, are narrowly bilimbate. Toward the ends, 

 they narrow rapidly to fine points. The hooks (fig. 24) have very 

 long shafts, enlarged to form a collar at the point where they pro- 

 trude from the- body surface. The distal end is bent to form a " head," 

 which on the lower surface carries a large tooth. Above this is a 

 much smaller tooth and above this several denticulations. A long 

 tuft of subrostral hairs extends beyond the large tooth. 



Type. — U.S.N.M. no. 20036, collected at station 35, latitude 18° 

 23'4o" N., longitude 67° i6'45" W.— latitude i8°24'45" N., longitude 

 67°i4'i5" W., in 80-100 fathoms. 



EXPLANATION OF PLATES 1 AND 2 



Figs. 1-6. Mclaenis tropicus, n. sp. Fig. i, head, X 13; fig. 2, first parapodium, 

 X 52; fig. 3, second parapodium, X So; fig. 4, seta, X 340; 

 fig. 5, seta, X 90; fig. 6, parapodium, X 90. 



Figs. 7, 8. Eupholoe acuminata, n. sp. Fig. 7, head, X 20; fig. 8, seta, X 60. 



Figs. 9-16. Eupholoe cirrata, n. sp. Fig. 9, head, X 10; fig. 10, first parapodium, 

 X 40; fig. II, dorsal portion of first parapodium, X 40; fig. 12, 

 second parapodium, X 40 ; fig. 13, posterior parapodium, X 20 ; 

 fig. 14, seta, X 240; fig. IS, seta, X 90; fig. 16, seta, X 240. 



Figs. 17-19. Hyalinoccia branchiata, n. sp. Fig. 17, head, X 5; fig- 18, para- 

 podium, X 40 ; fig- 19, seta, X 240. 



Figs. 20, 21. Alciopa mutilata, n. sp. Fig. 20, head, X 13; fig- 21, parapodium, 



X 30. 



Figs. 22-24. Maldanclla fimhriata, n. sp. Fig. 22, head, X 20 ; fig. 23, anal 

 funnel, X 20; fig. 24, seta, X 90. 



