DANFORTH: NEW PTEROPOD. 
General Features. 
The general external appearance of this pteropod is shown in figure 
1 (pi. 1) where, however, the parapodia and tentacles are somewhat 
retracted. Figure 2, A, (pi. 1) from a sketch of the living animal by 
Dr. Kingsley, shows these parts in their expanded condition. There 
are three well marked ciliated bands around the body: the anterior 
(pi. 1, fig. 1, ac) at the level of the paired lobes of the foot by which it is 
interrupted, the second (mc) at about the middle of the body, and the 
other (pc) near the posterior extremity. The band around the head is 
further characterized by being broken up into groups of cilia-bearing 
cells. A section through two of these groups is shown in figure 3 (pi. 
1) at ac and ac. Similar tracts in the anterior ciliated girdle have 
been described as characteristic of various pteropod larvae. There 
are also well developed cilia on the outer margin of the parapodia, 
on the median portion of the small lobes of the foot, on the osphradium, 
and about the mouth of the oral hood. 
The conspicuous appendages of the head are the tentacles and the 
lobes of the foot. The single pair of tentacles (pi. 1, fig. 1, i^) are located 
near the anterior end of the animal, one on either side of the opening 
that leads into the cavity containing the cephalocones and buccal mass. 
The foot, located on the ventral side of the head, is divided into three 
lobes essentially like those of the related forms. The anterior pair 
(a/) are small and somewhat retractile. When expanded to their 
fullest extent, the distal margins are directed outward and away from 
the median line. As stated above, their ventral surface is ciliated. 
The more posterior lobe (pf) of the foot is larger and usually directed 
backward. (See, however, figure 3, plate 1, where it is shown as bent 
forward in a retracted specimen.) Its musculature is weak and its 
structure delicate. This lobe shows no conspicuous cilia. The 
"wings" or parapodia arise from the neck just posterior to 'the foot 
and near the ventral side. When extended they appear as thin flat 
swimming organs more or less ovate in outline. In most of the pre- 
served specimens, however, they are in a retracted condition such as 
is shown in figure 1 (pi. 1). Their outer margins are furnished with 
long cilia. 
There are two conspicuous folds in the body : one where the pos- 
terior end is drawn in, the other just back of the head. These folds, 
especially the posterior one, may be nearly obliterated when the animal 
