146 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



in Valvata ; the oesophageal glandular swelling is distinctly Naticoid ; 

 the nervous system very closely approaches that of Lamellaria^ 

 Sigaretus, and Rissoia. 



Thus "we find that Adeorlis combines the characters of the Rissoiidae 

 and certain of the Naticidse, but still it differs in several important 

 respects from either of these families ; consequently I should be 

 inclined to retain the family Adeorbidse and place the same in 

 a position between the two families mentioned, regarding it on account 

 of its radula as somewhat more nearly allied to the Kissoiidse. 



BlBLIOGKAPHY. 



1. DtJPEEV, E., Shells of the Littoral Zone ... in Jersey: Ann. & 



Mag. Nat. Hist., ser. iv, vol. xviii (1876), pp. 338 and 343. 



2. Deshayes, Gt. p., Animaux sans vertebres dans le bassin de Paris, 



tom. ii (1864), p. 431. 



3. Marshall, J. T., in Jeffrey's Brit. Conch., vol. v, p. 216. 



4. Fischer, P., Note sur 1' Animal de V Adeorhis subcarinatus, 



Montagu : Journ. de Conch., vol. xxxiii (1885), p. 166. 



5. Bernard, F., Recherches sur Valvata piscinalis : Bull. Sci. 



France et Belgique, tom. xxii (1890), p. 253. 



6. Jeffreys, J. G., Brit. Conchology, vol. iv, p. 230. 



7. Troschel, F. H., Das Gebiss der Schnecken, Bd. i, p. 126. 



8. Haller, B., Die Morphologie der Prosobranchier, III: Morph. 



Jahrb., Bd. xviii (1892), p. 451. 



9. MooRE, J. E. S., The Molluscs of the Great African Lakes: 



Quart. Journ. Micro. Sci., vol. xli (1898), p. 181. 



10. BoirviER, E. L., Systeme Nerveux des Prosobranches : Ann. Sci. 



Nat., ZooL, ser. xvii, tom. iii, p. 1. 



11. Bttcquoy, E., Datjtzenberg, p., and Dollfxjs, G., Les Mollusques 



marins du Boussillon, tom. i (1882), p. 423. 



EXPLANATION OF PLATE VIII. 



Fig. 1. Adeorbis subcarinatus, as seen creeping on the side of an aquarium: 

 not fully extended. 



2. Operculum of Adeorbis. 



3. Radula of Adeorbis. 



4. Radula of -Sis«oi« ^«JTa. 



5. Alimentary canal of ^f;?(;or6«s (diagrammatic) . 



6. Restoration of the nervous system of Adeorbis, from above. 



7. Ditto, side view. 



8. Ditto of Bissoia, from above. 



9. Ditto, side view. 



b.d. bUe duct. pd.ff. pedal ganglion. 



b.ff. buccal ganglion. pl-ff- pleural ganglion. 



b.m. buccal mass. r. rectum. 



c.ff. cerebral ganglion. r.s. radula sac. 



cr.s. crystalline style sac. sb.ff. sub -intestinal ganglion. 



int. intestine. s.ff. salivary glands. 



0. otocyst. sp-ff- supra-intestinal ganglion. 



ces. cesophagus. st. stomach. 



o.f/. oesophageal glandular swelKng. 



