342 



NATURAL HISTORY. 



XXIX. Heterophrys* has an external villose or velvety layer of sarcode. 



XXX. Rapkidiopkrysf is an Actinophryii with a thick external layer of delicate sarcode, 

 which is full of minute siliciousC?) spicules, and extends for some way along the pseudopods. 



XXXI. Vampyretta,\ an animalcule not yet well understood; by some regarded as an 

 Actinophrys, capable of Amoeban variations of form, and making linger-like, lobate, and wave-like 



expansions of its sarcode. The presence of a nucleus is 

 doubtful ; and one marine form, having no nucleus, is 

 placed by Haeckel among his Monera. The fresh-water 

 Vampyrella feeds on the cells of the little Alga called 

 Spirogyra, Creeping on a filament, it perforates cell 

 after cell, transferring the contents to its own interior. 

 The marine Vampyrella, in like manner, feeds on the 

 Gompkone/ua. 



XXXII. Diplophrys is very minute, associated 

 in groups while young, but isolated when full grown ; 

 it then has a delicate envelope which permits of the 

 extrusion of only two tufts of attenuated pseudopods. 



XXXIII. Actinosphcerium\\ is larger than the Sun- 

 animalcule, sometimes 0-4 millimetre in diameter; it 

 looks much like it, and its habits are very similar, but 

 it is rarer, and the outer or clear vesicular portion is 

 very distinct from the interior clouded, though still 

 vesicular mass. The pseudopods are more distinctly 

 strengthened by a stiffer internal axis than in Acthto- 

 pkrys ; and yet the pseudopods can be retracted ; and 

 sometimes they wholly disappear. 



XXXIV. Acanthocystis [[ is like an Actinophrys; 

 but it has in some cases an external coat of delicate 

 protoplasm, full of exceedingly fine spicules (as in 

 Raphidiopkryg); and also, besides thin pseudopods all 

 over the surface, it has numerous long silicious spi- 

 cules or rays, often forked at the end, standing out 

 from every part of the body. 



XXXV. Hyalolampe ** has a body invested with 

 minute, clear, silicious globules. 



XXXVI. Clathrulina^ has an Actinophryan body invested with an elegant, globular, silicious 

 trellis, through which the pseudopodal rays project ; and this spherical latticed or fenestrated ++ 

 capsule is attached by a long, thin, silicious stem or "pedicle" to water-plants (Fig. 6). Young 

 individuals without the lattice skeleton rise from, and are attached to, the old ones. Adult forms, 

 however, have been seen which have divided, within the skeleton, into two or four parts, each of 

 which became encysted, and ultimately gave birth to a minute, nucleated, swimming atom ; and 

 this by-and-by became furnished with a trellis-coat and a fixed pedicle. 



XXXVII. Zooteira is also an Actinophryii with contractile pointed filaments, and elevated 

 on a pedicle ; but this is contractile, and not silicious ; and there is 110 skeleton. 



XXXVIII. Besides the Ifeliozoa, the Radiolaria comprise other kinds of Rhizopods. These 

 are marine, floating at or near the surface of the sea. Most have silicious frameworks ; and 

 their bodies are often of bright colours (yellow, red, violet, and blue, especially), either in spots or 

 diffused generally. One set (Plagiacanths|[||) have their sarcodic body divisible into a clear, toughish 



* Greek, hcteros, diverse ; ophri/s, an eyebrow. t Greek, raphis (idos), a needle ; ophrys, an eyebrow. 



+ From "Vampyre." Greek, diploos, double; ophrys, an eyebrow. |] Greek, act is, a ray; sphaira, a sphere. 



1 Greek, acantha, a thorn ; cyntis, a pouch. ** Greek, hyalos, crystal ; lampe, foam. 



ft Latin, clathri, a lattice. jj Latin, feneslra, a window. Greek, zoc, life ; tciro, I rub. 



Illl Greek, playios, oblique or transverse ; acantha, a thorn or spine. 



Fig. 6. CLATHRULINA ELEGANS. 



A, Completely developed : magnified more than 300 diameters ; 

 B, a zoospore, or " Swarm-spore," with two fiagella, a 

 nucleus (n), and several contractile vesicles i white spots). 

 Very highly magnified. (Copied from Allmati, after (A) Urn ff 

 B) Heitwig uiul Le 



and (B) 



esser.) 



