99 



2. P. plumula. Berthella porosa, Blainv. t. 167. f. 4. 



3. P. perforatus, Philippi, t. 171. f. 4. 



4. P. aurantiacus, Risso, t. \6J. f. 9, t. 167. f. 5 ; Cantraine, t. 1/4. 



f. 1; Philippi, t. 167. f. 3. 



5. P. De Haanii, Cantraine, t. 167. f. 2. 



6. P. brevifrons, Philippi, t. 171. f. 3. 

 7- P. . t. 169. f. 1. 



8. P. patagonicus, D'Orb. 1. 171. f. 1. 



9. P. cormitus, Quoy, 1. 174. f. 2. 



10. P. pttnctatus {Quoy, Voy. Ast. t. 22. f. 15, 19). 



11. P. tuberculatus, Meckel. 



12. P. stellatus, Risso. 



13. P. ocellatus, Chiaje. 



14. P. . Ruppell, t. 3. f . 2 ; t. 166. f. 1. Lepus marinus, 



Forskael, t. 169. f. 5. 



15. P. Blainvillii, Lesson, t. 172. f. 1. 



16. P. mammillatus, Quoy, 1. 174. f. 4. 



** Shell very small. 



17. P. testudinarius, Philippi {Moll. Sicil.) t. 20, 21. f. 1. 

 IS. P. mammillatus, Philippi, not Quoy. 



19. P. Forskalii, Chiaje, t. 169. f. 4. 



20. P. tuberculatus, Chiaje, t. 172. f. 2. 



21. P. reticulatus, Rang, t. 169. f. 3. 



*** Shell narrow, shelly 1 



22. P. oblongus, Savigny, t. 170, 173. f. 1. 



4. Oscanius, n. 325*. Mantle expanded, irregular. 



1. O. membranaceus. Lamellaria m., Montague, t. 103. f. 12. 



2. O. Lesueurii. Pleurobranchus L., Blainv. t. 166. f. 2. 



3. O. luniceps. Pleurobranchus 1., Cuvier, 1. 167. f. 2. 



5. Pleurobranch,*a, n. 327. 



1 . P. Meckeli, Blainv. t. 168. f. 1 ; Cuvier, 1. 168. f. 3 ; Chiaje, 1. 173. 



f. 2 ; Cantraine, t. 173. f. 3, from life. Pleurobranehidium della 

 Chaii, Verany, t. 220. f. 3, young. 



2. P. maeulata. Pleurobranehidium m., Quoy {Voy. Astrol.) t. 22. 



f. 12. 



6. PosterobranchjEA, n. 318. 

 1. P. maeulata, D'Orb. t. 168. f. 2. 



b. Gill on the inner edge of the front of the side of the mantle. 

 Foot small. Animal formed for floating . Allied to thePteno~ 

 branchiata, but the gills are not regularly comb-like, but 

 tufted, as in this Order. 



a. Foot compressed, erect, fin-like, with a small flat disk on the 

 hinder edge. Body and shell spiral or subspiral. Teeth, cen- 

 tral 1, lateral 33, elongate, unequal. Heteropodes, Lamk. 



Fam. 8. Pterotracheidm, p. 168. 



Body elongate, transparent. Gill, &c. in a small prominent bag, 

 naked, or covered with a thin subspiral shell. Operculum none. 

 Organs of generation in a common tubercle. 



H 2 



