134 systematic arrangement 



2. Atlanta. 



Shell shelly, transparent, keeled ; nucleus spiral, smooth. Oper- 

 culum spiral ; last whorl very large. 



1. A. Peronii, t. 117 c. f. 1 (not correct), t. 117 b. f. 5 (operculum 



incorrect), t. 117 b. f. 2 & 6, t. 240. f. 6. A. Keraudrenii, 

 t. 117 6. f. 4. 



2. A. Lamanoni, t. 240. f. 3. 



3. A. inclinata, t. 241. f. 1. 



4. A. brunnea, t. 242. f. 5. 



5. A. inflata, t. 241. f. 3. 



6. A. Gaudichaudi, t. 241. f. 4. 



7. A. Lesueurii, t. 241. f. 6. 



8. A. ? (A. bossue), t. 240. f. 5. 



9. A. depressa, t. 242, f. 4. 



10. A. Quoyii, t. 242. f. I. 



11. A. rosea, t. 241. f. 2. 



12. A. helicinoidea, t. 242. f. 2. 



13. A. involuta, t. 242. f. 3. 



14. A. turriculata, t. 242. f. 6. 



15. A. ?, n.s., t. 117c f. 2, 7. 



The central tooth of Atlanta Lesueurii rather broad, with an 

 acute recurved process on each side of the base ; the apex three- 

 spined, the middle largest ; the lateral teeth subequal, the first with 

 a large process behind, armed with a short spine. — Loven. 



The larva of Atlanta in the early state is oblong, with a ring of 

 cilia round the more truncated end ; then the foot and operculum 

 and the eyes are developed on one side of the disk, and when more 

 perfect, it has a broad fin divided into four narrow lobes in front, 

 and two broader ones behind, broad, strongly ciliated on the edges. 

 See Gegenbaur, Pteropoden, t. 8. f. 1-18. 



3. Steira. 



1. S. Lamanoni, Eschsch. Isis, 1825, 734. t. 5. f. 3 

 Most probably a badly observed Atlanta. 



