INFUSORIA. 47 



described them as Molluscs. From the end of the last cell of the 

 shell by one or more openings, or from numerous pores on the sur- 

 face of the shell, thin contractile threads are extended which serve 

 for motion. [On dissolving the calcareous matter from the shell of 

 living species, there always remains an organic base of the exact 

 form of the shell with all its pores and passages. This is a secre- 

 tion effected by the contained animal mass. ScHULTZE 1 .] EHREN- 

 BERG thinks that these animals are allied to the Bryozoa (the so- 

 called Polyps of Flustra, &c.) ; his principal reasons against their 

 arrangement in the class of the Infusories are, that they have no 

 polygastric intestinal canal, and that there is no other instance of 

 calcareous shells amongst Infusories. 



On this division compare, amongst other works ; D'ORBIGNY, Tableau 

 methodique de la Classe des Cepkalopodes, Ann. des Sc. nat. premiere S^rie. 

 Tom. VII. 1826. p. 245 315. PL 10 17. 



DUJARDIN, Observations nouvettes sur les Cephalopodes microscopiques. 

 Ann. des Sci. nat., seconde Serie. Tom. III. 1835. Zoologie, p. 108, 109 ; and 

 Recherches sur les Organismes inferieurs. 1. Sur la Gromia oviformis et sur 

 les Rkizopodes en general, ibid. Tom. IV. Zoologie, p. 343 352. PI. 9. 



EHRENBERG, Ueber dieBildung der Kreidefclsen u. des Kreidemergels durch 

 unsichtbare Organismen. Abhandl. der Jconiglich. Akademie der Wissensch. 

 zu Berlin. Aus dem Jahre 1838. s. 59 147. Also, Ueber nock sehr 

 zahlreich lebende Thierarten der Kreidebildung und den Organismus der 

 Polyihalamien, &c. Aus dem Jahre 1839. s. 81 174, especially s. 106 no. 



A. D'ORBIGNY, Article Foraminiferes, Dictionnaire universel d'ffist. nat. 

 par CH. D'ORBIGNY, Tom. V. 1845, P- 662 671. 



CLARK, On recent Foraminifera, Ann. of Nat. Hist. Sec. Series, 1850. 

 Vol. V. p. 161 171. 



CARPENTER, Microscopic Structure of Nummu1,ina, &c. Journal of the 

 Geol. Soc. of London, 1850. 



WILLIAMSON, On the minute structure of calcareous shells, &c. Trans. 

 Microsc. Society of London, Vol. III. 1851, and Quarterly Journ. of 

 Microsc. Science, 1853, No. IV. p. 87. 



EHRENBERG, Das ivirken des unsichtbaren kleinen Lebens auf der Erde, 

 1854, Tab. xix xxxn. Leipsig, 1854. 



MAX. SIGMUND SCHULTZE, Ueber den Organismus der Polythal. &c. 

 mit 7 illuminirten Tafeln, fol. Leipzig, 1854. 



On Noctiluca miliaris, which appears to belong to this division, though 

 it does not emit expansions externally but has a moveable appendage 



attached, see QUATREFAGES Ann. des sc. nat. sec. Serie Zool. xiv. p. -226 



2 35 PI- S> KROHN in Archiv f. Naturgesch. 1852 s. 77 81, Taf. 3, fig. 2. 

 It is a chief cause of the phosphorescence in sea-water. 



To this family belong also some fresh-water species. 



1 SCHULTZE, op. cti. p. 7. 



