PLATES IN VOL. XIL 



Plate I. Structure of Freshwater Algae. 



IL British Diatomaceae — Tessella, Tetracyclus and Fragilaria. 

 III. 



% 



IV. ^ Anatomy of Phalangium Opilio. 



VI. Machaerium subducens. 

 VII. Freshwater Algae. 

 VIII. "1 British Diatomaceae — Isthmia, Biddulphia, Amphitetras and 

 IX. J Meloseira. 

 X.-) 



XI. \ Irish Slugs. 

 XII. J 



xVv } ^*^"^t^^^ ^^ Shells. 



XV. 1 

 XVI. > Species of Pachyodon. 



XVII. New species of Parasites. 

 XVIII. British Diatomaceae — Meridion and Gomphonema. 



ERRATUM. 



The three concluding paragraphs appended to the notice of M. Chauvin's two memoirs, p. 124, 

 should have been annexed to the notice of M. Montagne's paper on the Podaxinece, and inserted 

 in page 113. 



