16 LINN.EAN GENERA. 



appearances on the surface of the shell : there 

 are sometimes many varieties of the same species. 

 " The Linnasan genera are thirty-six. I have 

 copied a list of them for you. In that tray are 

 the specimens mentioned in your list : 



ARRANGEMENT OF LINN^US. 



First Division — Multwalves : 3 genera. 



* Chiton, coat of mail, example, C. squamosa. 



* Lepas, acorn-shell or barnacle, ex. L. aiiatifera 



and ti7itinnahulu7n. 



* Pholas, stone-piercer, ex. P, Candida. 



Second Division. — Btvalces : 14 genera. 



* Mya, trough-shell, ex. M. triincata. 



* Solen, razor-sheath, ex. ^S'. siliqua. 



* Teirina, wedge-shell, ex. T. Feroensis. 



* Cardhcm, cockle, ex. C. cardissa. 



* Mactra, kneading-trough, ex. M. stultoriim. 



* DonaXj wedge-shell, ex. D. truncuhis. 



* Veiius^ Venus, ex. V. Paphia. 

 Spondylus, thorny oyster, ex. S. gcsderopus. 

 Chama, clamp-shell, ex.- C. gigas. 



* Area, ark-shell, ex. A. Noce. 



* Ostrcea, oyster, ex. O. isognornon. 



* Anomia. antique lamp, ex. A. ephippium. 



* Mytilus, muscle, ex. M. ediiUs. 



* Pinna, wing-shell, ex. P. pectindta. 



