CLASS PELECYPODA 
219 
Subgenus Teredops Bartsch. 
Teredo diegensis Bartsch, 1916. 
Nautilus, 30, No. 4:48. Bull U. S. N. M., 112; pi. 22, fig. 3; pi. 34, fig. 3. 
Shell small, sub-globular, white. The anterior area rather heavy, with 
the usual sinus which is edged with a strong callus slightly reflected over 
the back of the shell, from which it is not strongly differentiated. The rest 
of the anterior area is marked by dental ridges which have a strong down¬ 
ward flexure a little distance from the anterior edge, and then bend in an 
even curve backward, expanding slightly fan-shaped. These ridges are 
almost as wide as the spaces that separate them. There are 53 present in 
the type. They seem to slope almost as abruptly on the ventral side as 
on the dorsal, and are very finely denticulated on the free margin. The 
anterior median portion of the middle part is crossed by strong dental 
ridges which are separated by mere impressed lines and very strongly 
denticulated at the free edge. They join those of the anterior part at right 
angles. The junction between the anterior and median part is a slightly 
depressed groove which is crossed by rough wrinkles. The posterior 
portion of the median part is about as wide as the anterior and is marked 
by strong lines of growth. The posterior part forms a minute auricle 
which is marked by a series of obsolete corrugations which parallel the 
ventral margin. Interior bluish white. The junction of the anterior and 
the posteror portion is marked by a tumid cord. The auricle extends over 
the posterior median portion as a narrow shelf. The umbo has a strong 
knob from which a broad, curved and somewhat flexed blade extends for 
a little more than half the width of the shell. The ventral margin of the 
median portion bears the usual knob. The pallet has a sinuous, cylindric 
stalk. The blade is sub-cordate in shape. The distal portion is drawn out. 
The distal two-thirds are covered by a strong periostracum, the outer 
portion of which bears a strong calcareous knob at the tip. Height, 4.7; 
length, 4.4;; diameter, 4.6 mm. (Bartsch.) 
Type in U. S. N. M., No. 74219. Type locality, San Diego, California. 
Range. San Diego to San Francisco Bay, California. 
Subgenus Lyrodus Gould. 
Teredo townsendi Bartsch, 1922. 
Bull. U. S. N. M., 122:26; pi. 22, fig. 2, pi. 33, fig. 2. 
Shell small, sub-globular, white. The extreme anterior part with a 
strong sinus covered by a heavy callus, which is reflected over part of 
the outer portion as a thin callus, through which the dental ridges may 
be seen. These bend suddenly downward at the anterior margin, and then 
spread fan-shaped backward, being separated by spaces about three times 
