412 MONOTOCARDIA TAENIOGLOSSA chap. 



Fam. 4. Naricidae. — Tentacles broad in the middle, with 

 sessile eyes at the exterior base, propodium narrow, quadrangular, 

 a large epipodial veil on each side of the foot ; shell naticoid, 



cancellated, with velvety periostracuni. Jurassic . Single 



genus ; JVarica. 



Fam. 5. Xenophoridae. — Foot divided by a groove, anterior 

 portion the larger ; central tooth heart-shaped, with blunt cusps, 

 lateral large, roughly triangular, marginals long, falciform ; shell 

 trochiform, somewhat flattened, attaching various fragments 



externally. Devonian . Single genus, Xenophora (Figs. 



25, 26, p. 64). 



Fam. 6. Capulidae. — Ctenidium deeply and finely pectinate, 

 visceral sac scarcely spiral, penis long, behind the right tentacle ; 

 shell roughly patelliform, with scarcely any spire, interior 

 polished, usually with a septum or internal plate of variable form, 



no operculum. Devonian . Principal genera (Fig. 155, 



p. 248); Capulus, shell cap-shaped, no internal plate; Platyceras 

 (Palaeozoic, see p. 76), Diaphorostoina (Palaeozoic), Addisonia 

 (?) ; Crucibulum, internal appendage funnel-shaped ; Crepidula, 

 (including Crepipatella and Ergaea), shell 

 slipper - shaped, with a large septum ; 

 Calyptraea (including Galerus and Tro- 

 cJiita), internal lamina semi-spiral. 



Fam. 7. Hipponycidae. — Foot aborted, 

 animal sedentary, adductor-muscle shaped 

 like a horse's hoof, fastened on the ven- 

 tral side to the region of attachment, or 

 Fig. 272.— Two specimens of ^"^ ^ i\\u\ calcareous plate which closes 

 Crepidula (marked a and the aperture like a valve ; ventral side of 



h) on an old shell of, . , . i i i , i • i 



Murex radix Gn-iQ\. the body surrounded by a mantle with 



papillose border, whicli corresponds mor- 

 phologically to the epipodia, head emerging between the dorsal 

 and ventral mantles. Shell thick, bluntly conical, surface rugose. 



Eocene . Genera : Hipponyx ; Ifitrularia, a narrow half 



funnel-shaped appendage within the shell. 



Fam. 8. Solariidae. — Foot large, eyes sessile, near the outer 

 base of the tentacles, radula abnormal (}). 224) ; shell more or less 

 depressed, lip simple, umbilicus wide, margins often crenulated, 

 operculum variable. The proper position of the family is quite 

 uncertain. Ordovician . (i.) Solariinae. Genera : Sola- 



