44 MR.S.IIANLET ON THE LINNEAN MS, OF THE ' MUSEUM ULBIC.E. 



The generic arrangement exhibited in the manuscript differs 

 essentially from that which appeared in the final edition of his 

 ' Systema Naturae.' As a whole, it is decidedly inferior, yet it se^' 

 gregates certain natural groups, such as Lyra and Cassula, the 

 value of which have been acknowledged by all modern naturalists. 

 The following list and sequence of the genera comprised in it, can- 

 not, indeed, be regarded as an entire system, for certain groups, 

 viz.. Chiton, Lepas, Teredo, SabelJa, and the typical forms of Mya, 

 Mactra, and Anomia, were not at that period represented in the 

 Museum ; but it is not devoid of interest, since it manifests a trans- 

 itional stage in the progressive advance to that matured scheme 

 which was finally elaborated in the pages of his revised ' Systema.' 

 Dentalium. Haliotis. 



Patella. Nautilus. 



Nerita. Cymbium (=Argonauta). 



Helix. Spondylus. 



Turbo. Ostrea. 



Trochus. Pectcn. 



Turricula. Area. 



Bucciaum. Pinna. 



Lyra. Mytilus. 



Morion. Solen. 



Conus. Tellina. 



Voluta. Chama (not that of the 



Strombus (not that of the ' Systema'). 



' Systema'). Cunuus (=Yenus). 



Harpago (= Strombus). Pholas (not that of the 



Murex. ' Systema'). 



Cassida. Trimculus (=Donax). 



Cypr^ea. Bucardium (=Cardium). 



BuUa. 

 Besides the four genera {Chiton, Lepas, Teredo, Sahella) that 

 were excluded from this catalogue, either from the absence of speci- 

 mens, or from mistrust of their being veritable Testacea, six of the 

 remaining 32, namely, Pholas, Mya, Mactra, Chama, Anomia, and 

 Serpula, were likewise omitted, not being yet eliminated from So- 

 len, Bucardium, Spondylus, Ostrea, and Dentalium. To counter- 

 balance these, we find no less than eight subsequently abandoned 

 groupings : 



Turricula (an undefined amalgam of the long-spired species 

 of Buccinum, 3Iurex, and Strombiis). 

 Lyra (the Harpa and Purpura of the Lamarckian school). 



