144 MANUAL OF THE MOLLUSCA. 



Shell pyramidal, mth nearly a flat base ; ^vMrls numerous, flat, variously 

 striated ; apertui-e oblique, rbombic, pearly inside ; columella 

 twisted, slightly truncated ; outer lip thin ; operculum horny, 

 multi-spiral. Fig. 88 (T. pica). 



Animal mth 2 small or obsolete head-lobes between the 

 tentacles ; neck lappets large -, sides ornamented with lobes, 

 and 3 — 5 cirri ; gill very long, linear ; lingual teeth 11, den. Fig. 88. 

 ticulated ; uncini — 90, diminishing outwards. 



Distr., 150 sp. World-wide. Low-v»ater to 15 fathoms ; the smaller 

 species range nearly to 100 fathoms. 



Fossil, 360 sp. Devonian — . Europe, N. America, Chile. 



Sub-genem. Tyramis, Chem.n., Tr. obeHscus, PI. X., fig. 6, columella \ 

 contorted, forming a slight canal. '• 



Gibhda, Leach. Tr. magus, Brit. Shell depressed, \^^dely umbilicated ; i 

 whirls tumid. Head-lobes largely developed; lateral cirri 3. i 



Margarita, Leach. Tr. helicinus. PL X., fig. 7. Shell thin ; cirri 5 on | 

 each side. Distr., 17 sp. Greenland, Brit., Falkland Islands. Near low- i 

 water, under stones and sea-weed. ] 



Elenchus, Humph. (= Canthiridus, Montf.) E. ii'is. PI. X., fig. 8. ! 

 Smooth, thin, imperforate, with a prominent base. Australia, N. Zealand, i 

 F. iris scarcely diifers in form fi'om Tr. zizyphinus ; E. badiv.s is like a 

 pearly phasianella ; and E. varians (bankivia, jMenke) would be called a 

 chemnitzia, if fossilized. PI. X., fig. 9. 



EoTELLA, Lamarck. 1 



Etym., diminutive of rota, a wheel. (Syn., Helicina, Gray !) 

 Type, E. vestiaria. PI. X., fig. 10. 



Shell, lenticular, polished ; spire depressed ; base callous : lingual teeth 

 13 ; uncini numerous, sub-equal. 



Distr., 10 sp. India, Philippines, China, New Zealand. 



MoxoDONTA, Lam. 



Etym., monos, one, and ocloiis, (odontos) a tooth. 



Syn., labio, Oken. Clanculus, INIontf. Otavia, Risso. 



Tyi-)es, M. labeo. PI. X., fig. 11. M. pharaonis. PI. X., fig. 12. 



Shell, tm-binated, few- whirled ; whirls spirally grooved and granulated ; 

 lip thickened internally, and grooved ; columella toothed, more or less pro- 

 miaently and irregularly ; operc. horny, many- whirled. 



Distr., 10 sp ? W. Africa, Red Sea, India, Australia. 



Fossil, (included with trochus) Devonian — . Eifel. 



Delphinula (Roissy), Lam. 

 Etym., diminutive oi delphimts, a dolphin. (= Cyclostoma, Gray !) 



