38 Transactions of the Society. 



rest satisfied that the extruded pseudopodia were the tentacles of a 

 Cephalopodous animal. The first announcement of Dujardin 

 appeared in the month of January 1835 (Bibl. II.). In this note 

 he recorded that he had had opportunities of observing living 

 specimens of Miliolidse (Triloculina, Quinqueloculina), Vorticialis 

 ( = Polystomella), Kotalidse, Truncatulina, CristeJlaria, and others ; 

 and he was " convinced that the shell was not internal, but, on the 

 contrary, external, and that the animal, entirely wanting in organs 

 of locomotion or even respiration, was composed of a succession of 

 segments or lobes, which proceed by enlarging and enveloping one 

 another successively. No fleshy part {jpartic charnue) is visible on 

 the exterior excepting when a new segment is produced and is not 

 yet invested with shell-matter {encroute)!'' He crushed the shells, 

 and observed that the substance of the animal is as simple as 

 that of Planarians {jplanaircs), and even of Hydra, and he was the 

 first to decalcify the animals with weak acid, and observe that the 

 body is " formed of a series of segments occupying all the chambers 

 of the shell, capable of being unrolled, and presenting an aspect 

 differing according to the genera. Thus in Miliola the segments 

 are like spatulate leaves folded longitudinally ; in Polystomella 

 ( Vorticiale) ^ they are pieces in the form of a V, of which the two 

 arms embrace the preceding pieces and are bordered by lobes or 

 crenelations ; in Cristellaria the segments are crescentic, and con- 

 nected with one another by fleshy tubes whose number varies from 

 one to four, and increase successively in series of five segments. 

 On the other hand, the Eotalia, the ' Melonies ' ( = Alveolina),- 

 Truncatulina, etc., leave, after the treatment with acid, a trans- 

 parent membrane which envelops the segments and prevents their 

 isolation, and, furthermore, the last two have this membrane 

 furnished with prominent tubes in the intervals of which the 

 formation of the shell takes place." As a result of these observa- 

 tions he concludes that these creatures cannot be classed either 

 with Mollusca or with any of the groups already established in 

 the animal kingdom, and proposes for them the name " Symplec- 

 tomeres," indicating thereby that they are " formed of parts folded 

 together." ^ 



In June of the same year he returns to the subject (Bibl. III.). 



^ The generic name Polystomella was given by Lamarck in 1822 in substi- 

 tution for his original name Vorticialis (Lamarck, " Extrait Cours Zool.," 1812, 

 p. 122; and " Histoire des Animaux sans Vertebres,' Paris, vii. (1822) p. 625). 

 De Blainville in 1825 ("Manuel de Malacologie," 1825-27, p. 374, pi. vii., fig. 6J 

 used the term Vorticialis, but d'Orbigny in the " Tableau 5lethodique" restored 

 Lamarck's name Polystomella (p. 283). 



" As d'Orbigny justly pointed out in one of the first notes which he published 

 on his return from America, Dujardin had mistaken something else for this 

 genus, which is not to be found in the living condition on the shores of France. 



^ This notice appeared also in the Bulletin de la Soc. des Sciences Naturelles 

 de France, No. 3, 1835. 



