110 
LITHIDION. 
m 
1. sulcatum Gray. (Gray Phan. p. 124 . — Cy- 
clostomns sulcatus [Lithidion] Ad. Gen. p. 292. — 
Cyclost. lithidion Sow.) Mon. p. 
2. desciseens Pfr. (Proc. 1 8 5 1 . p. 243 . — - Ch. ed. 
nov. p. 262. t. 35. f. 25. 26. — Gray Phan. p. 124. 
— Cyclostomus dcsciscens [Lithidion] Ad Gen. 
p. 292.) 
3. Souleyetianuin Pet. (Coll. 195.-6%. ed. nov. 
p. 262. t. 35. f. 23. 24. — Gray Phan. p. 124. — 
Cyclostomus Souleyetianus [Lithidion] Ad. Gen. 
p. 292. Cyclostoma paradoxum Pfr. olim.) . 
4. dcprcssusn Sow. {Ch. ed. nov. p. 261. t. 35. f. 
17 — 19. — Gray Phan. p. 125. — Cyclostomus 
dcpressus [Lithidion] Ad Gen. p. 292.) .... 
5. nhcillU Pet. (Coll. 196. — Ch. ed. nov. p 261. 
t. 35. f. 20 — 22. — Gray Phan. p. 125. — Cyclo- 
stomus nivcus (Lithidion] Ad. Gen. p. 292.) . . 
176 . 
177. 
177. 
178. 
178. 
XXIV. Otopoma Gray. 
Pfr. Mon. Pneum. p. 179. — Gray Cat. Phan. p. 126. — 
Woodward Man. Moll. II. p. 176 : subgenus Cyclostomatis. — 
H. et A. Adams Gen. rec. Moll. II. p. 292 : subgenus Cy- 
clostomi. 
Conspectus speciemm. 
A. Umbilico prorsus clauso . . . . §. 1. Nr. 1. 
B. Umbilico magis minusve aperto. 
1. Peristomatis margine dextro expanso §. 2. Nr. 2 — 6. 
2. Margine dextro recto . . . . . §. 3. Nr. 7 — 15. 
3. Margine dextro flexuoso . . . . §. 4. Nr. 16 — 17. 
§. 1 . 
1. elaiiSMin Sow. (Gray Phan. p. 126. — Cycloslo- 
mus clausus [Otopoma] Ad. Gen. p. 293.) . . . Mon p. 179. 
$. 2 . 
2. auriculare Gray. (Gray Phan. p. 126. — Cy- 
clostomus auricularis [Otopoma; Ad Gen. p. 292. 
— Cyclostoma eandidum Sow ) - - 180. 
3. aHucaus Sow. (Gray Phan. p. 127. — Cyclosto- 
mus albicans [Otopoma] Ad. Gen. p. 292.; . . - - 181. 
4. natieoideg Keel. (Coll 197. — Gray Phan. p. 
127. — Cyclostomus naticoidcs [Otopoma] Ad. Gen. 
p. 293. — Turbo foliaccus Chemn., Dillw. Cat. II. 
p. 866. n. 121?) _ 181. 
