228 
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oe) 
10. 
16. 
BULLETIN OF THE BUREAU OF FISHERIES, 
DESCRIPTION OF FIGURES, 
PLATE VII. 
Newly attached larya of XY. gouldi. Sketched from life. The foot is shown fully extended. 
< 110. 
. Young shipworm of about 3 days’ attachment, from the ventral side. The shell is represented 
as transparent, with its outline shown faintly, to show the underlying gills at the sides of 
the visceral mass. 125. 
Specimen of about 1 week in the wood, slightly contracted, ventral view. To show especially 
the arrangement of the gills and the extent of the visceral mass. 95. 
Same stage as figure 3, from the left side. The worm-like form is being rapidly assumed. X 95. 
PLATE VIII. 
Young adult, from left side. The extension ofthe mantle over the shell, as the ‘‘ cephalic hood,” 
shown on the dorsal side of the latter. The mantle also extends forward over the posterior 
margin of the shell for a short distance. The siphons are represented as fully extended, but 
the pallets are not quite fully retracted. The mantle extends over the bases of the pallets 
as a collar. The attachments to the calcareous lining of the burrow of the muscles of the 
pallets (pp) and of the siphons (rs) are shown. The drawing was made from a slightly con- 
tracted specimen 10 em. long. 
Same as 5, the mantle removed to its line of attachment dorsally, at the two ends, removed 
to the midline. Lines with figures indicate the position of the sections from which figures 
28-35, inclusive, were drawn. 
PLATE IX. 
Larva a few hours after attachment, from the right side. The velar membrane has shrunken 
and the cells of the velum have been ingested. The shell, mantle, gill and liver lobe of the 
right side removed. The cells of the disintegrating velum are not represented. The foot 
not fully extended. 213. 
About the same stage as figure 2, from the left side. The left shell, mantle, and gill represented 
asremoved. The double origin of the cerebral ganglion is still shown. The visceral ganglion 
and kidney still lie in front of the posterior adductor. The czecum largely fills the foot, and 
has crowded the crystalline style and intestine to the left side. > 167. 
PLATE X. 
Same as figure 4, the left shell, mantle, and gill removed. The pericardial space, with the 
included and associated parts, has taken up a position posterior to the adductor muscle. 
The secondary czecum of the stomach has been formed. The gills project posterior to the 
visceral mass. 99. 
Adult, anterior half of the body, with the left shell valve, mantle, and gill removed, and the 
pericardial cavity laid open. Half of the posterior adductor removed. 
PLATE XI. 
Right shell valve of newly attached larva, internal view. The rudimentary apophyses are 
shown below the teeth. > 110. 
. Same, left shell valve. 
Shell of newly attached larva, end view. 110. 
. Shell of shipworm that has been in the wood about 1 day, front view. The first row of teeth 
upon the shell, the apophyses and the pivotal knobs have been formed. The shell gapes at 
both ends. 110. 
Left shell valve of specimen about 1mm.long. Oblique view. The larval shell still shown. 
x 110. 
Left shell valve of specimen 5 mm. long. X 23. 
