They are streaked with brown and purple and are housed in a transparent , gelatinous sheath composed of protein and chitin .
The massive siphons can be extended to two or three times the length of the shell and are joined together for their entire length .
siphons are streaked with brown and purple and are housed in a transparent , gelatinous sheath composed of protein and chitin .
The massive siphons can be extended to two or three times the length of the shell and are joined together for their entire length .