134 



are those nearest allied to the family of Conchacea. So nearly do the shells 

 of some species assimilate with those of Tapes, that it is difficult, concho- 

 logically, to separate them. The animal, according to the well-marked 

 typical V. Irus of our own shores, has, however, its mantle closed like 

 Gastroc/iana. Twenty-eight species were brought together a few years 

 since by Mr. Sowerby in his ' Thesaurus Conchyliorum/ and the shells are 

 characterized by a remarkable uniformity of detail. They are very unequal- 

 sided, the anterior side being particularly short, and their boring habit is 

 pretty well indicated by their irregularity of growth. They are all of a dull 

 white or stone-colour, tinged with yellow or rust, and some are richly 

 purple-stained in the interior. The sculpture is very uniform throughout, 

 the surface being more or less densely frilled with lamellae, which are some- 

 times serrated at the edge, sometimes a little festooned. The principal 

 habitats of the species are New Holland, New Zealand, the Philippine Is- 

 lands, and especially California. 



1. Carditoides, Lam. 



2. Ckinensis, Desk. 



3. Cordieri, id. 



4. crenata, Lam. 



5. Cumingii, Desk. 



6. cylindracea, id. 



7. derelicta, id. 



8. Diemenensis, Quoy. 



9. exotica, Hani. 

 10. fimbriata, Sow. 



Species. 



11. foliacea, Desk. 



12. insignis, id. 



13. interjecta, id. 



14. interstriata, Sow. 



15. Irus, Linn. 



16. macrophylla, Desk. 



17. niirabilis, id. 



18. mitis, id. 



19. rnonstrosa, id. 



20. Nuttallii, Com. 



21. obesa, Desk. 



22. oblonga, Sow. 



23. paupercula, Desk. 



24. planicostata, id. 



25. pulcherrima, id. 



26. rugosa, id. 



27. siliqua, id. 



28. tuuiida, Sow. 



Genus 2. PETRICOLA, Lamarck. 



Animal; oval ; mantle closed in front, except a small opening for 

 a lanceolate pointed foot ; siphons united for nearly half their 

 length, their orifices fringed with a double series of cirrhi, the 

 longer ones pinnated on one side. 



Shell ; triangular or narrowly oblong, the anterior side rounded, 

 the posterior more or less attenuated ; hinge composed of two 

 cardinal teeth in each valve. 



The Petricolce differ from the Venerupes only in having a shell of lighter 

 substance, attenuated obliquely instead of being subquadrate on the poste- 

 rior side, and in having a less lamellated sculpture. The sculpture, instead 



