APPENDIX TO CHAPTER XI 



177 



e. 2 . Aperture i-f length of shell ; 

 under lip with 2 or more teeth 



C 3 . Non-operculated ; aperture with canal at 

 anterior end ; our species 20 mm. or 

 less long . . . x . . 

 6 3 . Sinistral; whorls in contact. 



d. Shell ovate-globose, small, not over 5 mm. 

 long, transparent . . . ... 



c 2 . Shell elongated, turreted, slender, less 



than 30 mm. long. . 



c 3 . Shell large, over 100 mm. long, with pro- 

 duced anterior canal . . . 

 Shell flat, boat or cup shaped, if somewhat spiral, 



not forming a complete whorl. 

 61. Shell with apex somewhat spiral and an in- 

 ternal, usually horizontal, partition or dia- 

 phragm . .'..; . ; . 



6 2 ' Shell conical or cup-shaped, with apex turned 



forward ; no shelf or partition, 

 d. No perforation at apex or notch in mar- 

 gin .. . .... . 



c-2. Apex recurved ; margin or apex perfo- 

 rated 



Auriculidce 



(Ex. Melampus) 



Pleurotomidce 



Limacinidce 



Triforidce 



Fasciolariidw 



Calyptrwidce 

 (Ex. Crepidula) 



Acmceidce 



(Limpets) 



Fissurellidce 



