100 CONCHOLOGY. 



P. ungarica. The Fool's Cap. 



Conical, vertex slightly spiral, pointed, and recurved ; ex- 

 terior pale fawn colour, and the outer margin bordered with 

 a fringed epidermis ; interior sometimes of a very bright 

 pink or rose colour. 



5. Calyptrsea. The Cup and Saucer Limpet. Four species. 



This genus of shells is remarkable for having in the inte- 

 rior cavity a transverse funnel or tongue-shaped testaceous 

 appendage, from which originated its common name. 



Shell conic, base orbicular ; summit vertical and imper- 

 forated ; cavity deep, having at its interior summit a tongue- 

 like appendage. This appendage is sometimes vertical and 

 sometimes like a horseshoe, having on it a muscular impres- 

 sion of variable form. 



Calyptraea extinctorium. Calyptraea equestris. 



C. laevigata. C. tectum-sinense. 



C extinctorium. The extinguisher Calyptrsa. 

 Species in which the internal appendage is horn-shaped ; 

 colour brownish. 



C. equestris. The equestrian Calyptrasa. PI. 32, fig. 4. 

 Species in which the internal appendage is like a horse- 

 shoe, open in front. 



C tectum-sinense. The Chinese roof Calyptraea. 



Shell formed of separate, transverse, irregular round lam- 

 inae of uniform size, attached to each other by the summit 

 on the exterior of each, presenting the appearance of a num- 

 ber of small flat Patellce piled one on the other ; colour yel- 

 lowish, margin entire, very glossy within. 



6. Crepidula. The Slipper Limpet. Six species. 



Very similar to the Navicella, but distinguished from it by 

 not having an operculum. 



Shell irregular, form very variable, depressed or com- 

 pressed ; spire obliquely inclined to one side ; margin entire ; 



