Fig. 3. (A) Subvertebral sac pressure and brachial sac pressure during a breathing sequence in one C. marinus. Arrows indicate expiration events recorded in the subvertebral trace; note that rapid increases and decreases in brachial lymph sac pressure occur, but are predominantly during expiration. (B) Subvertebral sac pressure and pubic sac pressure during a breathing sequence in one C. marinus. Arrows indicate expiration events recorded in the subvertebral trace; note the rapid decreases in pubic sac pressure that occur during expiration.