Vlll CONTENTS. 



Page 

 On the Circulation of the Larvaa of Ephemerae, by N. Creutzburg ; 

 On the Existence of a Nervous System in Peltogaster, a Contri- 

 bution to the History of the Centrogonida, by M. Y. Delage ; 

 On the Pelagic Fauna of the Baltic Sea and Gulf of Finland, 

 by MM. G. Pouchet and J. de Guerne 494—498 



Hul^x 500 



PLATES IN VOL. XV. 



Plate I. Paramicippa tuberculosa. 



II. Cyproidia damnoniensis. 



III. Carboniferous Kirkbyse. 



IV. South-Australian Sponges. — Circulation in the Spongida. 



V. Idotea festiva. — Reproduction and Development of Rotifer 



vulgaris. 

 VI. Hystricrinus Carpenter). 

 VII. -, 

 VIII. [•Marine Polyzoa. 



IX. J 



X. Variations of Elapomorphus leinniscatus. 

 XL New Carboniferous Lycopods. 

 XII. . 



XIII. > New Sponges from Japan. 

 XIV. ) 



XV. New Freshwater Infusoria. 

 XVI. Ova and Embryonic Development of some Fishes, 



