248 



HARDWICKE'S SCIENCE-GOSSIP. 



results. He would like to know the effect from equal 

 masses at given distances. He considered Mr. Clark's 

 method of determining the percentage of magnetic 

 power extremely ingenious, and further experiments 

 were highly desirable. 



Fred. H. Davey. 

 Ponsanoolh, Perran-ar-worthal, Cornwall. 



HUNTING FOR ZOOPHYTES. 



DURING a hasty search for Hydroida and Poly- 

 (ii zoa in the tidal pools of Salcombe Harbour, 

 {vide Science-Gossip, 1890, p. 196), I think that no 

 two species afforded me greater pleasure in the sub- 

 sequent examination, from the fronds of algte, than 

 the specimens here figured of Bcania mimbilis and 

 Plumjilaria Catherina ; both were new to me, and 



stems present a very beautiful appearance, a definite 

 circulation being visible in every part of the growth. 

 Granular particles are visible in a colourless fluid, 

 which flows up to the extremities of the pinnae and 

 back again to the main stem. Whether it is true 

 protoplasm which is revealed, or merely the particles 

 absorbed by the polyps into a water circulation, I 

 am not prepared to say ; perhaps some more advanced 

 biologist can offer a definite opinion on the point. 

 In either case the organism is a singularly attractive 

 one for the live-cell, and I have watched the circu- 

 lation under the microscope with sufficient interest to 

 forget my dinner, until recalled to the ebb of time by 

 one in authority in such matters. 



Hundreds of the polyps, meanwhile, were dis- 

 porting themselves in full expansion, the eight 

 tentacles grabbing incessantly at particles in the 

 sea-water. Kick the table, and every polyp imme. 



Fig. 206. — Plumularia Catheriiia. 



Fig. 207. — Plumularia CatJurina. X 50. 



both possessed characters which appeared to be 

 worthy of observation. 



Plumularia Catherina is quite visible to the naked 

 eye. The fronds develop from creeping rhizomes, 

 some of the pinnate branchlets being upwards of an 

 inch in height, fragile in texture, and pale yellow in 

 colour. It is probably the most graceful of all the 

 Plumularios, as the pinnre wave in the flowing tide. 

 Examined beneath a low power, the transparent 



diately contracted, to expand again, however, in less 

 than two minutes. The stem is jointed or ringed 

 between each unilateral cell. The intermediate small 

 buds on each stem appear to have a tiny orifice, 

 connected, perhaps, in some manner with the circu- 

 latory system referred to. The vesicles are somewhat 

 pear-shaped, with circular rim slightly on one side. 

 The habitat of this elegant zoophyte is on the stems 

 of Fuci and Laminaria, in pools of the low-tide zone. 



