REPORT ON THE RADIOLARIA. 5>3 



production of radial, conical, or cylindrical tubules. These occur as well on the inside 

 as on the outside of the shell, and the tubules are now more conical, now more cylin- 

 drical ; their wall either solid or pierced by pores (Pis. 5-8). The tuljules are 

 commonly very irregular in form, size, and disposition ; distinguished, however, by a 

 number of hereditary peculiarities, which are sufficient for the distinction of genera. 

 Similar tubules occur also in some genera of solitary Ethmosphserida (Coscinomma, 

 Ethmosplicera, Conosphcera, &c., PL 12) ; but the tubules are here much more 

 regular and not so highly developed. 



Besides the tubules of the fenestrated shells, in some genera of Collosphgerida the 

 surface is armed with u-regular thorns, rarely with more regular radial spines. But these 

 spines obtain constantly the character of accessory by-spines, and remain short and 

 thin. In this family typical radial spines never occur in a regular and characteristic 

 disposition, corresponding to dimensive axes, as is the case in nearly all solitary 

 Sphseroidea, only excepting the Liosphserida. Commonly these spines or thorns 

 serve as protective arms for the shell-meshes, surrounding them often in the form 

 of coronels. Often the lattice-plate of the irregular roundish shell is tubercular, elevated 

 into irregular protuberances, bearing on the top a short spine or thorn (PL 8). 



The Central Capsule of the Collosphaerida is always a regular sphere, as in all 

 other S p h £e r o i d e a ; it is constantly placed within the lattice-shell, and commonly 

 much smaller than it, separated from it by a thick jelly-veil. A remarkable difference 

 from the solitary Sphseroidea is shown in the early division of the nucleus. 

 Commonly the central capsule of the CoUosphserida contains in its centre a large oil- 

 globule, surrounded by very numerous small nuclei. E. Hertwig estimated this 

 difference as so important, that he separated the social " Sphserozoea " and the solitary 

 " Peripylea " as two different orders. As already shown above (p. 7, 24), we cannot 

 support this separation, and are now convinced that this difference in the development 

 of the spores — just as in the C o 1 1 o d a r i a — is the consequence of an adaptation to 

 social life. 



The common jelly-body, in which the numerous central capsules and theii" envelop- 

 ing shells are united, exhibits in the CoUospheerida quite the same characters as in 

 the other social Radiolaria, the Collozoida and Sphserozoida. The jelly-body is very 

 voluminous, commonly spherical, often cyliudi'ical, of considerable size ; constantly 

 containing numerous large alveoles. Often each shell is enclosed in a sejiarate alveole 

 with rather solid wall (PL 6, fig. 2). Sometimes in the dead colonies all shells are 

 united in the central part of the jelly -body, whilst its peripheral part is comjjosed of a 

 stratum of large alveoles (PL 8, fig. 11) ; at other times no alveoles are visible (PL 7, 

 fig. 11). In many living colonies I found a very large spherical alveole with thick 

 wall in the centre of the spherical colony, surrounded by many strata of delicate thin-walled 

 alveoles (PL 5, fig. 1). In this case often the inner younger capsules were naked, 



