138 



PROF. ST. GEOllGE MIVAUT OX 



cohere in compound masses or colonies which may assume various 

 shapes — cylindrical, spheroidal, or like a chain, or even a circlet 

 of beads. There may be many more than a thousand zooids in 

 such aggregations, which may attain a length of 50 millims. 



In colonies, the gelatinous investment attains a greater size than 

 in most of the solitary forms. 



Fig. 1. 



Difi'crcul, forms assuiucd by colonics of (JoUozoum inerme. 

 (After Haeckel.) 



The name "Eadiolaria" was first used by the great John 

 Miiller, who in 1858 united together, under this designation, the 

 three groups known as Folycystina, Thalassicolla, and Acantho- 

 metra. 



The first E-adiolaria noticed were more or less indistinctly re- 

 ferred to in investigations as to the causes of marine luminosity 

 by Tilesius *, Bairdf, and Ehrenberg 



Two definite species, one simple and one compound {Physema- 

 tium and SpJicBrozoum), were distinctly indicated by F. Meyen § 

 as early as 1834. 



A great number of fossil kinds were subsequently made known 



* Naturalist to Kriisentern's Circumnavigation in 1803-1806. See Tilesius's 

 ' Ueber rlas nachtlicbe Leucbten des Meerwassers,' p. 867, tab. xx a. 



t Loudon's 'Magazine of Natural History,' vol. iii, 1830, p. 812, fig. 23a. 

 \ "Das Leuchten des Meeres, ' Abhandl. der k. Akad. Berlin, 1834, p. 411. 

 § Nov. Act. Acad. Leop.-Carol. vol. xvi. Suppl. 1834, pp. 159-164, t. xxviil. 



