on the Organic Composition of Chalk and Chalk Marl. 379 



care, and an improved and easier view is taken of the whole 

 subject. By his active exertions \m had collected between 600 

 and TOO species from the sea-sand of France, Italy, England, 

 the Isle of France, Sandwicli Islands, the Malouine and Ma- 

 rian Isles, See, of which, however, only 425 received names. 

 The whole mass of these microscopic animalcules, which he 

 again decidedly associates with the Mollusks andCephalopods, 

 but in a distinct order under the name of Foraminiferes, are 

 distributed by him into five families, according to the spiral 

 or other form in the grouping of the cells ; these families com- 

 })rising fifty-two genera. On this work Deshayes made vari- 

 ous critical remarks in the Dictionnaire Classique, D'Orbigny 

 expressly states that the animal of the Polythalamia (his Fora- 

 minifera) resembles the Sepia in the structure of its body, al- 

 though much smaller, and then proceeds to give the essential 

 characters of the living body of the Polythalamia, yet without 

 naming specifically or generically any one animal from which 

 they were taken*. 



Both Blainville and Dujardin have made the correct obser- 

 vation that the minute shells of the Polythalamia are external 

 cases, and not, as incorrectly viewed by Denys de Montfort 

 and Alcide d'Orbigny, internal bones. Yet in referring the 

 micrtiscopic so-called Cephalopods to the Infusoria, Dujardin 

 commits a mistakef. It was this contradiction between ob- 

 servers that induced Ferussac, in his great work, Histoire Na- 

 turelle des Molh/sques, to exclude the Foraminifers from the 

 class of the Mollusks; and others entertained similar objec- 

 tions, yet without assigning to them a correct position. 



In the year 1831 I laid before the Academy contributions 

 to the knowledge of Coral animals, with an attempt to class 

 them physiologically ; which attempt was entirely founded on 

 my own observations of the living animalcules, when, accom- 

 panied by Dr. Hemprich, I travelled on the Red Sea in the 

 years 1823 and 1825. In that work I designated the Coral 

 animals as composed of two strongly marked organically di- 

 stinct groups, under the names ofAnthozoa and Bryozoa. In 

 the year 1831 also, I communicated in the Symbolce Physicce 

 the first development made of the complicated structure of the 

 Halcyonella stagnoriim^ one of the Bryozoa, and showed that 

 it was quite similar to that of Flustra. 



The researches of Dujardin in 1835 gave an entirely new di- 

 rection to the ideas which had been formed of the Polythala- 

 mia, showing that not a trace of resemblance was to be found 

 between them and Sepia; on the contrary, the greatest sim- 

 plicity of structure became apparent, bespeaking a simple ani- 



* .innales dfs Sciences NatiircUes, 18i26, t. vii. p. 245. 



t Jnnak-s des Sciences Naturelles. Seconde Serie, t. iv. p. 343, 1835. 



