448 THE AMERICAN NATURALIST. | (VoL. XXXVI. 
longitudinal muscular layer. The glandular layer is in most 
regions so massively developed that it exceeds in thickness all 
the other layers of the body wall combined. The secretions of 
these glands furnish the sticky mucus by means of which the 
worms cling so tenaciously to the crab or to other objects. 
The outer epithelium is as in other genera, and is richly pro- 
vided with glands. 
The muscular layers of the body wall consist of a thin, 
external circular or oblique layer of muscles and an internal 
longitudinal layer (Figs. 7, 8), somewhat thicker than the former, 
but yet thinner than in most related genera. The lateral nerves 
occupy the usual places internal to the longitudinal muscular 
layer. In this species, however, they lie internal also to the 
thick layer of submuscular glands (Figs. 6, 8, 9, 7»), and there- 
fore nearer the center of the body than in other genera where 
these glands are not so highly developed. 
There is very little body parenchyma, the intestine filling 
most of the space internal to the glandular layer, except at the 
time when the genital products are developing. The pouches 
of genital products become enormously developed and encroach 
greatly upon the intestinal canal at the time of sexual maturity 
(Figs. 8, 9). The genital pouches extend much farther forward 
than in almost any other nemertean, reaching very nearly to the 
brain. The ovaries (Fig. 8, ov) are regularly paired, with a 
single large pouch containing usually from 12 to 30 ova between 
each pair of intestinal lobes. The spermaries, on the other 
hand, are far more numerous, surrounding the intestinal canal 
on all sides. As many as fifteen or more separate spermaries 
(Fig. 9, /) are sometimes found in a single transverse section. 
As in most parasitic animals the abundance of sexual products 
is greatly in excess of that in related non-parasitic forms. 
This is also well illustrated in Bergendal’s recent descrip- 
tion (00) of Gononemertes, a nemertean parasitic in the tuni- 
cate Phallusia. There is a resemblance also in other ana- 
tomical features, — in the excessive development of the cephalic 
glands, in the short posterior chamber of the proboscis, and in 
the slight development of the intestinal cæca. Of the two 
genera, Carcinonemertes appears to be far more degenerate than 
