REPOET ON THE PTEROPODA. 
97 
Table showing Proposed Classification of Pteropoda. 
Gastropoda 
Isopleura Anisopleura 
( = Amphineura) 
Streptoneura Euthyneura 
( = Prosobranchia and Heteropoda) 
Pulmonata Opisthobranchia 
Nudibranchia Tectibranchia 
1 . 
2. Pleuiobranchoidea 
( = Notaspidea). 
Bulloidea 
Aplysioidea 
( = Cephalaspidea) 
( - Anaspidea) 
Peltidse, 1 
Lophocercidae, 
Doridiidae, 
Aplysiidae, 
Gastropteridae, 
Pneumonoder mat idee, 
Philinidae, 
Clionopsidx, 
Aplustridae, 
Notobran ch x idx, 
Bullidae, 
Clionidse, 
Scaphandridse, 
Tomatinidae, 
Actaeonidae, 
IAmacinidx, | 
Cavoliniidaz, ( = Thecosomata). 
CymbuliidsR, I 
Halopsychidx, 
► ( = Gymnosomata). 
1 All the authors who allude to this family (Woodward, A Manual of the Mollusca, p. 187 ; Bronn, Die Klassen 
und Ordnungen des Thierreichs, Bd. iii. p. 795 ; Vayssiere, Recherches zoologiques et anatomiques sur les Mollusques 
Opistobranches du Golfe de Marseille, loc. cit., p. 104 ; Fischer, Manuel de Conchyliologie, p. 573) have regarded these 
Molluscs as Pleurobranchcidea. They are, however, true Bulloidea, as is shown by the conformation of the head, of the 
generative organs, and of the nervous system. 
(ZOOL. CHAI.L. EXP. PART LXVI. — 1888.) 
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