300 PROP, ALLMAN ON THE RECENT BE8EAECHES 



of two kiuds of reproduction, by division and by cy st-formatiou . 

 The former takes place within the capsule, and consists in the di- 

 vision of the contents by a transverse constriction. One of the 

 two portions thus formed soon forces its way out through the per- 

 forated capsule, and then lives for some hours in the surrounding 

 water as a free naked sarcodic body resembling an ActinopTirys. It 

 ultimately secretes a capsule and stem, and becomes a perfect Cla- 

 thrulina. 



In the second kind of reproduction there are formed within 

 the capsule, by a process apparently of budding, numerous rounded 

 sarcode-masses, each of which becomes enveloped by a firm cover- 

 ing ; and they thus remain for months as spherical cysts within, 

 the common capsule. Grreeff has further examined these bodies, 

 and has shown that they contain within them a large pale nucleus, 

 and that the walls of the cyst are set round with short spines, 

 and are probably siliceous. 



When the time has arrived for their further development, the 

 sarcode contents slip out of their cysts and escape into the sur- 

 rounding water through the latticework of the capsule. Here 

 they swarm about for some hours in the form of ciliated oviform 

 embryos, then become transformed into free Actinophrys-\\\.e 

 organisms, which finally acquire the stem and siliceous lattice-like 

 capsule of the perfect animal. 



The resemblance of the siliceous perforated capsule of Clathru- 

 lina to the latticed shells of the Polycystina is sufficiently obvious ; 

 and we must admit, with Grreeff, that, if we met with these little 

 capsules free in the open sea, we should not hesitate to refer them 

 to the true Polycystina, and place them in Haeckel's Eadiolarian 

 family of the Ethmosphseridas. In the more essential points of 

 structure, however, Clathrulina has no close affinity with the 

 Eadiolaria, f rom which it is widely separated by the absence of a 

 central capsule with its multicellular contents. The absence of 

 yellow cells is another, though less important, point which opposes 

 itself to the association of Clathrulina with the true Radiolaria. 

 Notwithstanding these differences, however, Grreeff does not hesi- 

 tate to refer it to the Eadiolaria, and place it there, in the family 

 of the Ethmosphseridae. 



Another Desmothoracous genus has been described by Hertwig 

 and Lesser under the name of Hedriocystis. Like Clathrulina, 

 the body is enclosed in a single-chambered stalked test perforated 

 for the passage of pseudopodia ; but instead of being liard and 



