188 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
over the shell till it rests on its beaks, the syphons waving at the 
same time. The syphons are united, the branchial syphon 
twice the width of the anal syphon. When fully expanded the 
syphons are nearly the length of the shell; they are curved 
dorsally. A line between the syphons extends half-way down. 
The anal syphon shows a dome-shaped valve encircled with 
twenty-eight papillae of slightly varying lengths; these are 
short, rising from square bases. A band of brown markings is 
seen just below the papillae. The opening of the branchial 
syphon is fringed with thirty-three papillae, some long, others 
very short irregularly alternating. These papillae are white with 
brown spots at their bases and a brown mottled line marking; 
Fig. 41.— Afociro solidissima Dillwyn. 
the middle of the papillae lengthwise. The papillae are all 
incurved. Within the opening of the branchial syphon arise 
two excessively stout papillae springing from the wall in con- 
junction with the anal syphon. They are curved outward and 
extend half-way across the opening. One of these is bifurcated 
(Fig. 41, a). Brown markings appear between the syphonal open- 
ings. Minute papillae are seen on the sides near the* ends of the 
syphonal tubes running back a short distance. These short 
papillae appear again on the base of the branchial syphon and on 
the mantle bordering the pedal opening. The mantle appears just 
beyond the edge of the shell. The syphons are richly marked 
with brown; the palpi are long, ribbon-shaped, moving freely 
in every direction and independent of each other, at times twirled 
