PROTOZOA 



21 



Fain. 3. TIIALASSICOLUDA. lYripyhea devoid of a skeleton, or 

 with a skeleton composed of loose siliceous spicules only. Nucleus 

 single ; central capsule and general protoplasm s|ilierieal. 



Ccncra (selected). Thal,if:*i<vU,i, Huxley (Fig. XIII., Fig. 

 XIV. 1) ; Thalassospfitsra, Haeck. ; J'/ti/- nmiii'm, llaeek. 



Fain. 4. POLYCYTTARIA. Peripvhea consisting of colonies of 

 many central capsules united by their eztracapsulai protoplasm. 

 Central capsules multiplying Ijy fission. Nuclei in each central 

 capsule numerous. Siliceous skeleton cither absent, or of loose 

 spicules, or having the form of a spherical fcncstrated shell sur- 

 rounding each central capsule. 



Genera (selected). Collosphssra, Mnller (with fenestrated globular 

 skeleton); SjiJuerozoum, Haeck. (skeleton of numerous loose spicules 

 which are branched); J!:i/i!iii!ii:uitin, Hacck. (spicules simple); Col- 

 faouin, Miiller (devoid of skeleton, Fig. XIV. 2, 3, 4, 5). 



1 



each encloses a crystalline rod. c, yellow cells hing in tin- extraeapsnlar 

 protoplasm. 5. A small colony of Colluzott at. iu< riu<', magnified -J5 



diameters. a, alveoli (vaeuolus) of tlie extraeapsular prntdjilasni ; 6, 

 central ea]isub s. each eontainiiiL.' besiilrs ].rotupla>Tn a hove oil-globule. 

 6-13. Yellow cells of various Kailiolai ia : (J, normal yellow cell; 7, 8. 

 division \\itb I.M ination of transverse septum ; it, a modilieil ronililiim 

 aeeonling to llraii'H ; in, division of a yellow cell into four ; 11, amieboid 

 condition of a yellow cell from the bu.ly of a dead Sphicro/.onn ; 1:2, a 

 similar cull in process of division ; 13, a yellow cell the protoplasm of 

 which is ereeping out of its cellulose envelope. 14. //'V/n..,y,/, < i -". 



in, riiiii, Hacck., living example; x 400. a, nucleus; i>, central capsule ; 

 c, siliceous basket-work skeleton. IS. Two swarm-spore* (tla^-llnhe) 



of Coltozoitiii in<'fn>i', set fl'cu trom such a central capsule as that drawn in 

 4 ; each contains a crystal b and a nucleus a. n;. Two swarm-spores 



of Collozoum iiicrmc, of the second kind, viz., devoid of crystals, and of 

 two sizes, a macrospore and a microspore. They have been set free 



from central capsules with c tents of a dilferent appearance from that 



drawn in 4. a, nucleus. 17. Acttnomma asteracanthion, Haeck ; x 200; 

 one of the i'eripyloca. Entire animal in optical section, a, nucleus; 

 6, wall of the central capsule ; c, innermost siliceous shell enclosed iu the 

 nucleus; c\ middle shell lying within the central capsule ; c 2 , outer shell 

 lying in the extraeapsular protoplasm. Four radial siliceous spines, hold- 

 ing the three spherical shells together arc Been. The radial fibrillation of 

 the protoplasm and the fine extraeapsular pseudopodia are to be noted 

 18. Amphilonche M<'.(IH> H.S, Haeck; x 200; one of the Acanthometridea. 

 Entire animal as seen living. 



ORDER 2. MONOPYL&A, Hertwig. 



Characters. Silico-skeletal Kadiolaria in which the central cap- 

 sule is not spherical but monaxonic (cone-shaped), with a single per- 

 forate area (pore-plate) placed on the basal face of the cone ; the 

 membrane of the capsule is simple, the nucleus single ; the skeleton 

 is extraeapsular, and forms a scaffold-like or bee-hive-like structure 

 of mouaxonic form. 





FIQ. XIV. Eadiolaria. 1. Central capsule of Thalamcolla nucleata, 

 Huxley, iu radial section, a, the large nucleus (Binnenblaschen); b, 

 corpuscular structures of the intracapsular protoplasm containing con- 

 cretions ; c, wall of the capsule (membranous shell), showing the fine 

 radial pore-canals ; d, nucleolar fibres (chromatiu substance) of the 

 nucleus. 2,3. Collozoinn i/ien/ie, J. Miiller, two dilferent forms of 



colonies, of the natural size. 4. Central capsule from a colony of 



Collozoum iturme, showing the intracapsular protoplasm and nucleus, 

 broken up into a number of spores, the germs of swarm-spores or flagellulc; ; 



one of the Monopyhea. 

 central capsule ia 

 ch it is lodged. 



Fam. 1. PLECTIDA, Haeck. Skeleton formed of siliceous spines 

 loosely conjoined. 



Genera (selected). Pliiiiufimtlta, Haeck. ; Plcgmatium, Haeck. 



Fam. 2. CYRTIDA, Haeck. Skeleton a monaxonic or triradiate 

 shell, or continuous piece (bee-hive-shaped). 



Genera (selected). JL>1 hili/jilra, Haeck. ; Eueyrtidium, Haeck. 

 (Fig. XV.); CarpocanlttM. Haeck. (Fig. XVI. 3). 



Fam. 3. BOTIUDA, Haeck. Irregular forms ; the shell composed 

 of several chambers agglomerated without definite order ; a single 

 central capsule. 



Genera. Botryocyrtia, Haeck. ; Lithobotrys, Haeck. 



Fam. 4. SPYKIDA, Haeck. Gcmmiuate forms, with shell con- 

 sisting of two conjoined chambers ; a single central capsule. 



Fam. 5. STEPHIDA, Hacck. Skeleton cricoid, forming a single 

 siliceous ring or several conjoined rings. 



Genera (selected). Acanthodesmia, Haeck.; Zygostcpkanus, 

 Haeck. ; Lithocirms, Haeck. (Fig. XVI. 1). 



ORDERS. PHJIODARIA, Haeck. (Triinjlasa, Hertwig). 

 Characters. Silico-skeletal Kadiolaria iu which the central 



