PLATES IN VOL. XH. 



Plate L Structure of Freshwater Algas. 



II. British Diatomaceae — Tessella, Tetracydus and Fragilaria. 



IV. > Anatomy of Phalangium Opilio. 



V.J 

 VI. Machserium subducens. 

 VII. Freshwater Algae. 

 VIII. 1 British Diatomacese — Isthmia, Biddulphia, Amphitetras and 

 IX. / Metoseira. 



Xi. I Irish Slugs. 

 XII. J 

 XIII. |, 



XV. -1 



XVI. Y Species of Pachyodon. 

 XVI.»J 



XVII. New species of Parasites. 

 XVIII. British Diatomacese — Meridian and Gompho7iema. 



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. Montague's paper on the Podax'inece, and inserted 

 in page 113. 



