EUPOLYMNIA INSULANA. 435 



same distance as the smooth fold and bears throughout its length a dense series 

 of thin lamellae, which cross it longitudinally and completely conceal it. Behind 

 the lamellated region is a transverse series of numerous small, distally rounded 

 papillae. No eye-spots are evident. Ventrally, between the lower ends of the 

 folds above described, there is a thick oblong fold, or lower lip, marked by longi- 

 tudinal sulci and depressed below the level of the succeeding somite. A half 

 ring is elevated above and laterally caudad of the tentacular lamellated ridge 

 into a thick, rounded ridge, or collar, which is nearly smooth above, but laterally 

 is more manifestly wrinkled. Behind this is a complete ring deepened a little 

 below the level of adjacent parts; ventrally it extends forward between the 

 ventral ends of the collar, and is there along its anterior border elevated into a 

 low, rounded ridge behind which the surface is strongly wrinkled and tubercular ; 

 the roughening also affects the lower part of the sides of the ring, but not the 

 dorsum. 



The next somite is ventrally much shorter than the preceding or the follow- 

 ing one; it is broadly elevated ventrally along the anterior border, the elevation 

 becoming higher laterad and on the lower part of each side forming a low, thick, 

 somewhat twisted, lobe, or flap; the elevation and lobes are longitudinally 

 creased or wrinkled. In the next, or third, somite this elevation is not present 

 in the median ventral region, which is depressed and usually marked off in large 

 areas by anastomosing sulci, but at the sides of the venter the border is similarly 

 elevated into a low, rounded ridge, which, on the lower part of each side, but a 

 little more dorsad than in the preceding somite, develops into a fold larger than 

 the preceding one. The next, or fourth, somite is similarly modified, but the 

 median ventral region, free from a distinct ridge-like fold, is larger. No such 

 ridges and folds are present on following somites. 



As judged by scars, there are three pairs of branchia; of these, two branchiae 

 on the right side alone remain in the type, and the caudal, a member of the 

 third pair (or fourth somite), is much the larger and more complicated. It is 

 1.8 to 2 mm. long, and has a stout cylindrical trunk, constituting the greater 

 part of this length, and gives off on one side a branch, which immediately breaks 

 up into three or four other branchings, each of which divides twice, or less com- 

 monly, thrice, the final one or two branches being dichotomous and the ultimate 

 branches comparatively short and thick; several other, closely overlajiping 

 branches arise farther distad, these presenting the same mode of branching. The 

 second branchia, in line with and immediately in front of the one just described, 

 presents a much more slender stalk, at the distal end of which are three short 



