4 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
is fully expanded, but when it is contracted, the posterior end and the 
head with its appendages are almost completely hidden behind them. 
The anus (pi. 1, fig. 1, a) and opening of the nephridium occur close, 
together just in front of the anterior fold and a little to the right of 
the median line. The nephridial opening is lateral to the anus, but 
when the animal is not fully expanded there may be a slight infolding 
about the two openings forming a kind of short cloaca. To the right 
of these openings is the strongly ciliated osphradium. This structure 
appears as a protruding lobe which, as may be seen in figure 1 at o, is 
rather noticeable. Figure 3 (pi. 1) shows the osphradium and the 
underlying ganglion (og) in section. 
The common genital opening is close to the attachment of the right 
fin and dorsal to it, while the penial opening (pi. 1, fig. 1, po) is to the 
right of the foot and below the anterior ciliated band. I have been 
unable to find any groove or ciliated line running between the two. 
In this, as in most allied genera, there are retractile cephalocones 
surrounded by the oral hood, but here they present a most unusual 
condition in their lack of symmetry. In other genera where these 
cones are present there are two or three pairs of them, or (Dexiobran- 
chia) there is one pair and a median cone. In Paedoclione, however, 
there are two cephalocones on the right side of the buccal mass and 
only one on the left, this last being the longest. Relationships seem 
to show that the left cephalocone is the antimere of the dorsal one on 
the right side, the left ventral cephalocone being therefore lacking. 
Some study was made of the structure of these cones which so far as it 
went, revealed no marked differences from the condition described for 
Clione by Pclseneer ('85). In all the specimens examined, the as\Tn- 
metrical cone (the ventral right) showed more secretion in the glandu- 
lar internal cells than occurred in the similar cells of the other cones. 
Whether this really indicates a differentiation in the cones or whether 
it is an accidental coincidence I am unable to say. Figure 3 (pi. 1) 
from a slightly obli(|ue section through the head at about the level 
of the first band of cilia, shows the cut surface of the three cones and 
their position in the cavity (rcl, ccl' , and ccr). 
The integument of Paedoclione is unpigmented, but the large single- 
celled dermal glands described by Gegenbaur for Pneumodermon and 
other forms are also conspicuous in this pteropod. That these glands 
are evident in the living animal is shown in Dr. Kingsley's drawings. 
They present no features at variance with Gegenbaur's description. 
