28 



HARDWICKE'S SCIENCE-GOSSIP. 



ROSSENDALE RHIZOPODS. 

 No S. 



IN our previous papers we have treated upon the 

 Rhizopods belonging to the order Protoplasta, 

 which is divided into two sub-orders, Lobosa and 

 Filosa ; in the present article we arrive at the order 

 Heliozoa. This contains nine genera, and sixteen or 

 more species. The Rhizopods of this order differ 

 widely, in many important particulars, from those of 

 the previous one. Some of them are very beautiful, 

 from the presence of chlorophyll as a permanent 

 constituent of their bodies ; others are, perhaps, 

 more curious than beautiful ; while a considerable 

 number are very obscure, and in some cases offer 

 considerable difficulty to a successful identification. 

 The animals of this order are essentially swimmers, 

 and are most commonly found among Algre and duck- 

 weed. They consist generally of a more or less 

 spherical mass of naked, foamy protoplasm. 



In one genus, Clathrulina, there is a beautiful 



Fig. 12. — Actinophrys sol. 



latticed, globular, stalked, silicious test. In Vampy- 

 rella, the spherical body can assume ameboid forms, 

 and in addition to the ordinary pseudopodial rays, 

 there are others which are Acineta-like, and the 

 periphery of the body can be thrown into conical and 

 lobose extensions. The species of Diplophrys are 

 mostly minute, and generally associated together in 

 numbers, each having fine pseudopodia radiating 

 from its opposite poles, and an interior coloured 

 (amber or red) spot. 



Acanthocystis has many both curious and beautiful 

 species, which are characterised by the body being 

 invested by a layer of protoplasm densely crowded 

 with minute linear particles, and by the presence of 

 simple, pin-like, or furcate silicious radiating spines. 

 In Raphidiophrys there is also an exterior layer of 

 protoplasm extending in tapering processes on to the 

 pseudopodial rays, and densely pervaded with minute 



spicules tangentially arranged ; the Rhizopods of 

 this genus are generally compound, being found [a 

 groups of variable numbers joined by isthmus-like 

 bars. The genus Heterophrys is Actinophrys-like, 

 but the body is invested with a layer of granular 

 protoplasm, having a villous surface. In Hyalolampe, 

 the protoplasmic body is covered with a layer ot 

 minute, colourless, silicious globules. Although I 

 have seen several species belonging to at least three 

 of the above genera, it is quite evident that they are 

 somewhat rare forms in this district, and as in the 

 instances mentioned I was unable to devote time to 

 their study, I do not propose in these articles to 

 describe any of the above genera, confining my notes 

 to the two genera, Actinophrys and Actinospherium. 

 I think it probable that the Rhizopods of the order 

 under consideration are southern forms, delighting in 

 the genial warmth of a less rigorous climate than that 

 of Rossendale. I know that, with the exceptions to 

 be stated presently, none of my microscopical friends 

 have been more fortunate- than myself in the 

 collection of the Heliozoa ; while, on the other hand, I 

 have frequently come across them in tubes of the 

 Rotifera sent me by kind correspondents from various 

 parts of the Midland counties and the south of 

 England. Actinophrys sol,* or, as the older micro- 

 scopists termed it, "The Sun Animalcule," appears 

 to be as common here as elsewhere, being found 

 in all our waters, particularly those well supplied 

 with duckweed and other aquatic plants. Few 

 possessors of microscopes, I should imagine, have 

 not frequently had this Heliozoan Rhizopod under 

 observation. It presents itself generally as a colour- 

 less, globular, more or less cellular-looking body, 

 covered with long, delicate, hair-like rays. As it 

 placidly floats in the water, it seems entirely unfitted 

 to cope with its more active neighbours ; but obser- 

 vation proves it to be able to look well after its 

 commissariat. Although it is to some extent at the 

 mercy of the slightest current, it is able to anchor 

 itself to some stationary or floating object. It is a 

 somewhat sluggish, and apparently a stationary 

 animal, but if carefully watched it will be noticed to 

 slowly glide along by some obscure movements of its 

 pseudopodial rays. The body, as stated above, is 

 generally colourless, but coloured food-balls, red, 

 green, or brown, may sometimes be observed 

 embedded in some part of its substance ; these, after 

 digestion has continued some time, appear as coloured, 

 cloudy patches. The body is granular, and seems in 

 some individuals so vesicular as to present the appear- 

 ance of cellular tissue, though not often as definitely 

 so as in Actinospherium. The pseudopodia are very 

 numerous, but variable in different specimens ; they are 

 as long, or even twice as long, as the diameter of the 

 body, and are very delicate, and capable of retraction. 



* The vesicles in the figure of A. sol ought to have been 

 shaded. 



