282 A. EARLAND ON RADIOLARIA. 



Ehrenberg, Mliller, Haeckel and Hertwig were the principal early 

 workers in the field, and, up to 1887, 810 various forms had been 

 described by them and others. In 1887 Haeckel published the 

 result of his ten years' labour at the material collected by the 

 Challenger Expedition, adding no less than 3508 new species 

 to those previously known, and making a total of 739 genera 

 and 4318 species. Prodigious as this number may appear, the 

 distinguished author expresses an opinion that it is by no means 

 exhaustive, and that '' a careful and patient worker who would 

 devote a second decade to the work would probably increase the 

 number of new forms (especially of the smaller ones) by more 

 than a thousand ; but for a really complete examination, the 

 lifetime of one man would not suffice." 



Explanation of the Plates. 



The figures have all been reproduced, by kind permission of 

 Sir John Murray, K.C.B., from the Report on the Radiolaria 

 of the Challenger Expedition; and I should like to express my 

 thanks to my friend Mr. A. J. French, a member of the Club, 

 for the care which he has displayed in their reproduction. The 

 letters have the same meaning in all the figures. 



\a = central capsule, aa = extensions or apophyses of the 

 central capsule, as = astropyle. c = calymma. n = nucleus. 

 nu = nucleoli, v = vacuoles, al = alveoles, o = oil globules. 

 X = xanthellse. r sp =■ radial spines of centrogenous skeleton. 

 2JS = pseudopodia. p = podoconus. ph = phseodium, php>h = 

 phseodellse. pr = proboscis. s\ •= skeleton. p)P ~ lateral 

 parapylse.] 



Plate 15. 



Fig. 1. A Radiolarian of the First Legion (Spumellaria),. 

 Cladococcus ahietinus, Haeckel. A portion of the calymma, etc.,. 

 has been removed to show the surface of the lattice sphere, 

 through the pores of which the central capsule, which was 

 originally entirely enclosed, has thrust out numerous club-shaped 

 extensions or apophyses. The central spherical nucleus fills about, 

 half the shell cavity. X 160 diameters. 



