The long, slender, white, unpigmented cephalic tentacles are up to 70% of shell length when fully extended.
The head has a short stout snout. Large,extendible outer lips can be held in a variety of positions, sometimes, as in this image, resembling a large snout. The lips are thin and flimsy when extended, but are reinforced internally by longitudinal ribs that, when held together, give the lips a wavy edge.
Touch sensitivity of the cephalic tentacles and outer lips, plus that of the pallial tentacles, is probably the main means of warning of attack.
APPENDIX re range advance/retreat: flic.kr/p/2jW74ig