APPENDIX. 345 
Suborder 2. Tectibranchiata (Pleurobranchus, Aplysia, 
Bulla, Tornatella, ete.). 
Subdivision II. Lingual membrane strap- or ribbon-like, rhachis 
and pleura distinctly differentiated, dental processes re- 
curved (Anclodonta). 
Order 1. Heteroglossa (Gray). 
Suborder 1. Polyplacophora (Chiton, Chitonellus). 
Suborder 2. Cyclobranchia (Patella, Patina). 
Suborder 8. Cervicobranchia (Tectura, Gadinia, Lepeta). 
Suborder 4. Cirrobranchia (Dentalium). 
Order 2. Rhachidoglossa (Gray ). 
Suborder 5. Dicranobranchia. Gills two, symmetrical on 
the back of the neck (Scutus, Doridobranchus, Emargi- 
nula, Puncturella, Fissurella). 
Suborder 6. Schismatobranchia. Gills in two plumes on the 
left side of the gill cavity (Teinotis, Padollus, Haliotis, 
Scissurella). 
Suborder 7. Scutibranchia. Gills in a spiral line on the left 
side (Stomatella, Trochus, Turbo, Rotella, Nerita, Neri- 
tina, Navicella). 
Suborder 8. Pseudobranchia. No distinct gills (Helicina, 
Proserpina, Ceres). [Nearly all of the groups of subdi- 
vision II of ‘“‘ Moneecia,” are known to be diecious.—G. 
We Ded. 
Division II. Dicecia. 
Subdivision I. Lingual membrane unarmed, or with pleural 
teeth only. 
Order 1 (without name). 
A. Rhachis and pleurz unarmed (Pyramidellidze, Cancel- 
lariide). [Cancellaria has an armed radula. | 
B. Pleural teeth simple [Toxoglossa, Troschel ] (Pleuro- 
tomide, Acusidx, Conidee). 
C. Dentition, Pavimental [ Ptenoglossa, Troschel ] (Sola- 
riide, Scalariide, Janthinide ). 
Subdivision II. Lingual membr ane strap- or ribbon-like. 
Order 1. Proboscidifera. 
Suborder 1. Orthodonta. Dental processes pointing directly 
backwards [| Rhachiglossa, Troschel ]. 
A. Lingual dentition uniserial (Yolutide [See suborder 
IT}). 
iB: idee dentition triserial. 
a. Khachis and pleure comb-like. 
Dental processes numerous, small. 
Strap short (Mitride). Strap long. Teeth short 
(Fasciolariide). Teeth long (Fuside). 
Dental processes few and large (Turbinellide), 
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