41 8 MONOTOCARDIA — TAENIOGLOSSA chap. 



Fam. 34. Verinetidae. — Visceral sac greatly produced, 

 irregularly spiral, no copulator}^ organs (radula, Fig. 126, p. 

 223), shell tubular, irregularly coiled, last 

 whorls often free, aperture circular; operculum 

 corneous, circular, nucleus central. Carbo- 

 niferous . Principal genera: Vermetus; 



Siliquaria (Fig 153, p. 248), a long fissure, 

 or series of holes, runs along a considerable 

 part of the shell, operculum with outer face 

 Fig. 276. -Develop- spiral, elevated. 



ment of Coec^<m.• A, ^„ orry, t-t t-«. it 



showing the gradual ^ -^^*^- ^o. ^Stromoidae. — i^ oot narrow, arched, 

 formation of septa; metapodium greatly produced, snout long*, eye 



a, apex; ap, aper- -, , . ,i . i ,1 , r , -^ 



ture; ss, first sep- peduucies long, thiCK, cycs elaborate, siphon 

 turn ; 8s\ second ghort, pcuis prominent, bifurcate ; central tooth 



septum. (After de . . -^ "■ _,. • i p i t 



Foiin.) B, adult With strong median cusp, marginals laicitorm, 

 formof C'.e6wmeM/H slender, edge more or less denticulate; shell 



Ad. Panama x 10 ^ o ^ 



solid, spire conical, outer lip generally dilated 

 into wings or digitations, channelled before and behind, a labial 

 sinus at the base, distinct from the anterior canal ; operculum small 



for the aperture, corneous, claw-shaped, edge notched. Lias . 



Genera : Stromhus (Fig. 99, p. 200) ; Pereiraea (Miocene), 

 Pteroceras (Fig. 277; digitations of the outer lip very strong), 

 Rostellaria (spire produced, anterior canal very long), Rimella^ 

 Pterodonta, Terehellum (base of shell truncate, spire short). 



Fam. 36. Chenopodidae (^= Aporrhaidae) . — Foot flat ; lateral 

 and marginal teeth not denticulate ; shell resembling that of 

 Stromhus^ outer lip dilated, wing-like, no labial sinus. Jurassic 



. Genera: Chenopus (^ = Aporrhais^ Diastema^ Malaptera, 



Harpagodes^ Alaria (last four from Secondary strata). 



Fam. 37. Struthiolariidae. — Radula allied to that of iS'^rom^ws, 

 marginals occasionally multiplied ; shell buccinoid, very solid, 

 outer lip thickened, canal short, operculum claw-shaped, notched, 



nucleus terminal. Tertiary . Single genus, Struthiolaria 



(subg., Perissodonta^ marginal teeth multiplied). 



Fam. 38. Cypraeidae. — Mantle with two large lateral lobes 

 reflected and meeting over the shell, siphon small ; central and 

 lateral teeth bluntly tricuspid or multicuspid, laterals fairly 

 broad, edges cusped or finely pectinate ; shell polished, solid, 

 spire generally concealed in the adult or overlaid with enamel, 

 aperture straight, narrow, nearly as long as the shell, toothed at 



