64 M. Dufo on the Mollusca of the 



mimicate a more detailed account of the organization of the 

 infusoria of red snow, upon my obtaining an opportunity of 

 examining this remarkable production under more favourable 

 circumstances. 



EXPLANATION OF THE PLATE. 



Fig. L A portion of the colouring mat- 

 ter of the red snow. 

 Fig. 2. a, Globules of the Protococcus 

 nivalis Ag. 

 by A globule whence the spo- 



rules are escaping. 

 c, A globule surrounded with 

 globules of the Protococcus 

 nebulostis of Kutz. 



Fig. 3. Astasia nivalis, Shuttl. 



Fig. 4. Gyges sanguineus, Shuttl. 



Fig. 5. "1 Other coloured infusoria of 



Fig. 6. J red snow. 



Fiff' 8 I ^^^^^ uncoloured do. 

 Fig. 9. Monas gliscens, Ehrenb. 1 

 Fig. 10. Protococcus nebulosus, 

 Kutz. 



It is to be observed that all these figures were examined through a micro- 

 scope which magnified 300 diameters. 



Beport on a Memoir entitled " Observations on the Marine^ Land^ 

 and Biver Mollusca of the Seclielles and Amir antes Islands, 

 By M. Dufo." By M. Blainville. 



The knowledge of animals does not consist merely in an ac- 

 quaintance with their external and internal organization, their 

 specific distinction, and their position in the natural series. 

 The consideration of these may be said to be reserved for pro- 

 fessed zoologists, because, in order to do it aright, preliminary 

 study is requisite, the inspection of collections, books of de- 

 scription, and especially of iconography. But the knowledge 

 of the manners and habits of animals is equally required, things 

 which, although often the evident deduction from peculiarities 

 of organization, are not always certainly ascertained from that 

 source. The study therefore, of living animals in their natural 

 haunts, their relations with the soil, with the medium in which 

 they live, with the other organized bodies on which they sub- 

 sist, or to which they afford nourishment, and their mode of 

 propagation, is of so much importance, that, in the common 

 opinion and language, it seems to form the whole science. 



It is to this important part of our knowledge of the mollus- 

 cous animals, or to their natural history, that the labours of 

 M. Dufo are calculated to add a considerable number of new 

 facts, which will be doubly augmented in value when we re- 

 flect that, in order to acquire them, it was necessary to have 



