MUSEUM OF COMPARATIVE ZOOLOGY. 197 
The intestine is more globular in shape than the esophagus, opening internally 
into the stomach, and externally through the anus. Its inner walls are cil- 
iated, and its cavity is partially filled in many specimens with feces. 
In a second slightly older larva (Fig. 11) of Polygordius, several additions in 
structure have been made, and marked modifications in form have taken place. 
In the general outline, the most important change is the flattening of the whole 
larva, especially on the lower hemisphere, by which the equatorial axis is rel- 
atively very much increased, The flagellum on the apex of the upper hemi- 
sphere has disappeared, and the two ocelli have drawn still more closely 
together; so that both now lie very close to the apical pole. The stomach 
has become more elongated in shape, while the cesophagus has assumed a more 
tubular form. The beginnings of the funnel-shaped bodies described by 
Hatschek in the European Loven’s larva can be seen as two globular sacs (¢), 
one on each side of the stomach, on a level just above a plane passing through 
the equatorial ring of cilia. Two prominent fibres arise from the collection of 
cells upon which the ocelli are placed, and pass to the lips above the mouth. 
Two other threads have a similar origin, and extend meridionally on each 
side of the stomach to the clusters of cells on the inner walls of the lower 
hemisphere, at the anal pole of the body. A third pair of threads, hitherto 
unnoticed, take their rise from the same clusters of cells at the anal pole, and 
extend parallel with each other to the lower lips of the mouth. They end 
near two pigment bodies which are constantly found in this region. 
The different larval stages in the development of Loven’s larva which lie 
between that represented in Fig. 11 and the adult Fig. 18 have been figured by 
Hatschek for the European species, and for the American representative by 
A, Agassiz. New figures of the American larva are introduced in order to 
show the peculiar brown bodies found about the bell margin, which seem to 
be characteristic, and the two ventral “nerve cords” shown in Fig. 14, vn, 
which are unrepresented in any drawings of these larve which have been pub- 
lished. With the exception of these two differences, our common Loven’s larva 
is similar to the European. 
Capitella (young). 
A larva referred to the genus Capitella has been taken several times in our 
Newport fishing. These were always in the same condition as that figured in 
Plate III. Figs. 19, 20, and do not differ essentially from one already repre- 
sented by Claparéde and Metschnikoff.* 
Lumbriconereis. 
Plate VII. 
The cove near the laboratory is the home of many genera of Annelides which 
live in the fine mud covering the bottom in many places. In the months of 
June, July, and August, a plentiful supply of eggs in all stages of growth, 
* Op. cit. 
