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 6. f. 5 (operculum 



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

 t. 117*. 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. 117 c. 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. — Lovbn. 



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. Ms, 1825, 734. t. 5. f. 3 

 Most probably a badly observed Atlanta. 



