IXUliX. 
XI 
Order I. — PULMONI A — (continued ) . 
Pupa, 35 
Chondrus, 35 
Succinea, 35 
Clausilia, 36 
Achatina, 36 
P ulrnonea Aquatica. 
Onchidium, 37 
Planorbis, 37 
Limn;«us, 38 
Physa, 38 
Scarabaeus, 38 
Auricula, 39 
Conovulus, 39 
Order II.— NUDIBRANCHIATA, 39 
Doris, 40 
Onchidora, 40 
Plocamoceros, 40 
Polycera, 40 
Tritonia, 41 
Thethys, 41 
-Scyllaea, 41 
Glaucus, 42 
Laniogerus, 42 
Eolidia, 42 
Cavolina, 42 
Flabellina, 43 
Tergipes, 43 
Busiris, 43 
Placobranclius, 43 
Order III.— INFEROBRANCHIATA, 43 
Phyllidia, 44 
Diphyllidia, 44 
Order IV.— TECTIBRANCHIATA, 44 
Pleurobranchus, 44 
Pleurobranchaea, 45 
Aplysia, 45 
Dolabella, 46 
Notarchus, 46 
Bursatella, 47 
Akera, 47 
Bulloea, 47 
Bulla, 48 
Akera proper, 48 
Gastroptcron, 48 
Gastroplax, 49 
