ONUPHIS CRASSISETOSA. 297 



The first three metastomial somites form a region strongly set off from the 

 remaining part of the body by reason of the greater length and the greater 

 height and convexity of these three somites ; they also differ in having the para- 

 podia attached at the anterior end and in having them bent more strongly 

 forwards, and they are less sharply separated from each other than are the 

 succeeding ones. The first metastomial somite is five times as long as the peri- 

 stomium, and across its wider anterior end is not fully twice as wide as long 

 {cir. 8 :5) . The second metastomial has the same length and breadth but appears 

 to be more narrowed caudad. The third metastomial is much shorter {cir. 

 25:17) and is also narrower. The fourth is abruptly much shorter than the 

 third (10:17) and is in the type 3.6-3.8 times wider than long. The succeeding 

 somites increase gradually in width to the tenth or twelfth metastomial and 

 in the type retain nearly the same proportions, but in the paratype are longer 

 after the first five, somites X-XII, etc., being about three times wider than 

 long. 



The first parapodia are bent du*ectly forwards along the sides of the peri- 

 stomium and nearly attain the front margin of the prostomium, which its post- 

 setal process exceeds; the proximal end is thick, conically narrowing to the more 

 slender and cylindrical main portion; the notocirrus is attached near the middle 

 of the dorsal surface, is constricted at base, and as a whole slender and pointed ; 

 the neurocirrus is attached on the opposite surface, but at the base it is similar 

 in form and equal in size, or nearly so, to the notocirrus. The distal end of 

 the parapodium presents a prominent, cirrus-like, postsetal process which tapers 

 to a point from a moderately wide base and has its tip nearly on a level with 

 that of the notocirrus where both extend directly distad. (Plate 43, fig. 3). 

 The second parapodia are much shorter than the first and are directed ecto- 

 cephalad and somewhat ventrad instead of directly cephalad; the cirri and 

 postsetal finger are of essentially the same length and form as in the first. 

 (Plate 43, fig. 4) . The third parapodia are again shorter than the second and are 

 directed more ectad ; the notocirrus remains equally long and of the same form, 

 and the postsetal process is but little reduced; on the contrary, the neurocirrus 

 has a decidedly different form, appearing as a short, stout, rounded prominence. 

 (Plate 43, fig. 5). In the fourth (Plate 43, fig. G) and all succeeding parapodia, 

 the neurocirrus is evident only as the usual flattened scale merged in the ventral 

 glandular area. The notocirrus continues well developed on all parapodia to 

 the end of the fragments, but caudad becomes, as usual, much more slender. 

 The postsetal process becomes gradually reduced to a low, pointed process, and 



