THE PELAGIC NEMERTEAN NECTONEMERTES 469 
less than half way to the brain commissures (figs. 14, 17), where 
it merges into the stomach (st), likewise a narrow tube; from 
the stomach the slender pylorus (pyl) leads backward for a short 
distance and opens, as in other related forms, into the dorsal 
wall of the intestine (in). The intestine extends anteriorly 
beneath the pylorus and stomach as a broad pouch, or caecum 
(ic), which reaches forward to the posterior brain region and 
sends paired lateral diverticula dorsally above the gonads and 
the proboscis sheath. These diverticula (acd, figs. 14, 17) are 
broad, irregularly lobed, and are so closely placed that they leave 
but little of the body parenchyma between them. ‘The diverti- 
cula of the caecum are scarcely to be distinguished from those of 
the intestine proper, but tend to be somewhat more irregular in 
outline by having rather deeper lobes. 
The intestine, with about sixty pairs of broad diverticula, 
extends posteriorly nearly to the end of the body. Figures 1 
and 10 show how completely these intestinal diverticula fill the 
space within the body walls. Indeed, in the more contracted 
specimens the diverticula are much more closely crowded to- 
gether than is shown in figure 1. In the living animal, on the 
other hand, they are doubtless more widely separated than here 
shown, for, as stated above the best-preserved specimen has 
contracted in alcohol to one-fourth its original volume, and this 
shrinkage must have come largely from the parenchyma which 
separates the intestinal diverticula. The diverticula are all 
irregularly lobed, but not branched, both vertically and _ hori- 
zontally, and for the most part appear more or less distinctly 
bilobed distally when seen from the dorsal surface (fig. 1). They 
conform to the general outline of the body except in the regions 
of the tentacles and the horizontal lateral fins, as well as in the 
caudal fin, where lateral extensions of the body walls beyond the 
general outline of the body occur (figs. 1, 8, 9). Immediately 
anterior to the caudal fin the diverticula become shorter and 
gradually decrease in length posteriorly (fig. 1) until they dis- 
appear in the short and narrow rectum (figs. 1, 9) which opens 
at the very extremity of the body. 
