REPORT ON THE RADIOLARIA. 1543 



Family LXXI. PH^ODINIDA, Haeckel (PI. 101, figs. 1, 2). 



Phceodinida, Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. Jena, Dec. 12, p. 4. 



Definition. PH^ODARIA without skeleton. Central capsule with one to three (or 

 more) openings, placed in the centre of the spherical naked calymma. 



The family Phseodinidais the simplest and most primitive of the PHJSODARIA, and 

 differs from all the other families of this legion in the complete absence of a skeleton. It 

 bears, therefore, the same relation to the latter as the Thalassicollida do to the other 

 SPUMELLARIA. The soft body is only composed of the central capsule with the nucleus, 

 and the calymma with the phseodium. 



Of course it is quite possible that the skeletonless PH^EODARIA, which we regard 

 here as the ancestral family of that legion, may be either members of other families 

 which have lost their skeleton accidentally, or young PILEODARIA which have not yet 

 developed a skeleton. But in some preparations of the Challenger certain large, well- 

 preserved PH^EODARIA, without any trace of skeleton, are not rare; and since I myself 

 have observed a complete living Phceodina, I have no doubt that they are independent, 

 primordial forms (like Actissa, Thalassicolla, Cystidium, Nassella, &c.). Probably 

 also two skeletonless PH^ODARIA belong to this family which are figured by R. Hertwig, 

 in 1879, in his Organismus d. Radiol. (Taf. x. fig. 1,11); this author, however, supposed 

 that they had lost their original skeleton. 



The three species of Pha3odinida which are described in the sequel represent two 

 different genera, Phceodina and Phceocolla, already distinguished in my first note on the 

 PH^EODARIA (Sitzungsb. med.-nat. Gesellsch. Jena, 1879, Dec. 12, p. 4). Phceodina is a 

 true TRIPYLEA, and has the usual three openings which occur in the majority of PH^EO- 

 DARIA, a large astropyle or main-opening on the oral pole of the main axis, and a pair of 

 lateral accessory openings, or parapylse, on the aboral pole. Phceocolla, however, has 

 only a single opening, the astropyle, and agrees therefore with those PELEODARIA which 

 possess no parapylse (Challengerida, Medusettida, Castanellida, &c.). 



The complete body is in all observed Phseodinida a small jelly sphere of 1 to 3 mm. 

 in diameter, with a transparent cortical layer and an opaque dark central part. This 

 latter is the phseodium, in which the central capsule is hidden, surrounded on all sides 

 by the gelatinous spherical calymma ; the smooth surface of the latter is spherical. 



The central capsule of the Phseodinida (PI. 101, figs. 1, 2), is either spherical or 

 spheroidal, somewhat lenticular, slightly depressed in the direction of the main axis. Its 

 diameter is between "15 and 0'25. Its double membrane exhibits the same structure 

 as in the other PH^IODARIA. The thick, double-contoured outer membrane is separated 

 from the thin and delicate inner membrane by a clear space, filled up by jelly or by a fluid ; 

 the two are connected in Phceocolla (fig. 1) only at the astropyle, in Phceodina (fig. 2) 



