DANFORTH: NEW PTEROPOD. 7 
cephalocones and buccal mass are entirely retracted within the hood. 
The mouth at the apex of the buccal cone is oval or slit-like, having its 
longest diameter running dorso-ventrally. The lips (I) are slightly 
thickened and supplied with a number of simple glands such as are 
also present about the margin of the oral hood. Both lips and ankistro- 
phores (to be discussed presently) are supplied with small muscles 
which extend down to the posterior side of the buccal mass. 
In various other genera a pair of structures dorsal to and in front 
of the radula are called "hook sacks" because of the hooks they bear 
and because when retracted they are inverted as sacks into the wall of 
the pharynx. When expanded they project as cones and the hooks, 
lying on the outer surface, are in position to function in holding the 
food. In Paedoclione the structure differs from this type. The hooks 
are seated merely on cushions of thick connective tissue, in the normal 
position, but apparently with little power of distention or retraction — 
certainly they are not capable of retraction into a sack as in other 
genera. Hence the term "hook sack" is inapplicable and so for these 
structures and the homologous hook sacks of other forms I would sug- 
gest the term ankistrophore (ay Kiarpov, hook). Each ankistrophore 
bears a few (not more than eight) hooks. Each of these hooks con- 
sists of a large (epithelial) cell, the free surface of which projects as a 
strong process beyond the adjoining cells. This process is covered 
with a dense chitinoid (?) material Avhich forms the functional hook. 
Figure 4 (pi. 1) shows these structures in section. 
The radular teeth, represented diagrammatically in figure 5 (pi. 1) 
are arranged according to the formula 5. 1. 5. The lateral teeth are 
somewhat falcate in shape with widened bases. Their chitinous tips 
point backward. The median tooth is broad, flat, and without cusp. 
Among the specimens examined, I find only one or two with more than 
fifteen ranks of teeth. 
As the figure (pi. 2, fig. 6, sa) shows, the salivary glands are of 
moderate size. They empty into the pharynx behind and dorsal to 
the radula. The contents of the glands is so strongly stained in all the 
specimens that I can make out almost nothing of its structure. 
The esophagus, normally of small diameter, is surrounded by circu- 
lar and longitudinal fibers. For the most part it is nearly straight, 
though in a few retracted individuals it is bent a little. Its epithelial 
lining is ciliated. This lining is raised into folds which perhaps are 
secretory in character as is the case in Clionopsis calceola (Peck, '90). 
