INVERTEBRATA, CRTPTOaAMIAj MICROSCOPY, ETC. 467 



ing tlicmselvcs. It is, of course, possible to say that this separation 

 was due to the commencing decomposition of the sponge ; on the other 

 hand, it was certain that the parent-sponge was still in full vital 

 activity. \\ hen the free buds were studied, it was found that they had 

 broken olT at the point at which they were budded off, and tliat at this 

 point the process was elongated into the ordinary flask-neck shape, 

 so tliat they now represented young specimens of the species, and had 

 their spicules turned m the ordinary direction. Large specimens of 

 Leucosolenia never present this mode of reproduction. Is it possible 

 that, as the author suggests, we have to do with an alternation of gene- 

 ration, and that the products of sexual reproduction reproduce them- 

 selves by gemmation ? 



Protozoa. 



Shepheardella— a new Type of Marine Rhizopoda.* — Mr. J. 

 D. Siddall describes and figures Shepheardella keniformis, a new genus 

 and species of Rhizopods, from Tenby. 



The body of the Rhizopod is unicellular, elongated, and abruptly 

 pointed at both ends, flattened and ribbon-like when in a state 

 of activity, rounded and worm-like when at rest. It is furnished 

 with a flexible, transparent, colourless integument of considerable 

 firmness ; and the whole tubular cavity is densely filled with 

 yellowish, coarsely granular protoplasm, having a very distinct 

 oval nucleus, and occasionally also a few scattered non-contractile 

 hyaline vesicles. The sarcode rotates in a regular stream around 

 the interior of the integument, and carries the nucleus alon" witli 

 it, the current performing a complete circuit within the cell. Tlie 

 nucleus is seldom carried entirely round the cell, being as a rule 

 intercepted in its course along one stream and passed over into 

 the opposing one before it has travelled fur from the centre in 

 either direction. The opposing streams of sarcode thus formed on 

 the two sides of the cell are not separated from each other by 

 any clear line, as in Characeae, though otherwise much resembling 

 the phenomenon observable in the living vegetable cell. The principal 

 ditferenco between the two is in the direction of the current, that of 

 Chara advancing in a spiral direction, while that of Shepheardella 

 completes its circuit in one plane, the two currents slightly overlap- 

 ping each other. Tlie integument is perforated at each end by a 

 minute aperture, through which some of the sarcode passes and collects 

 into a small mass. From this mass a very delicate coating spreads 

 over the whole exterior surface of the integument, and this tiiin layer 

 occjvsitmally throws out a psoudopodium. But the great network of 

 inosculating and branching pseuiloj)odia are at the two extremities of 

 the organism, extending themselves from the terminal niasstis of sarcodo 

 to a distance considerably exceeding the whole length of the body. 

 The circulation of the liner granular sarcode in the psoudopodiu is 

 easily traced. It is very rapid, advancing and returning in single 

 double, or even triple streams, aecording to the breadth of the j)seudo- 

 podiuni traversed, so that from tho rotation of the chief mass of sar- 

 code within the test and tho external circulation in tho pseudopodia, it 

 * 'Quart. Jourii. Mi^r. S<m..* xx (18S0) p. 130 (2 pinfcs). 



