540 



SYSTEMATIC HISTORY OF THE INFUSORIA. 



Astasia hcsmatodes (xvni. 86, two 

 figs.). — Body fusiform or spindle-shaped 

 when extended j tail very short; body 

 green at first, afterwards of a blood-red 

 colour. The illustrations represent one 

 creatiu'e extended, and another con- 

 tracted. Hampstead. 1-380". This spe- 

 cies is referred by Dujardin and Carter to 

 the genus Euylena. 



A. Jlavicans. — Extensible, cone- 

 shaped, approaching cylindrical, and 

 rounded at the foremost extremity. Tail 

 very short and blunt; granules of a 

 yellowish colour. In yellow ditch- 

 water. Length about 1-430". 



A. pusilla. — Extensible, cone-shaped, 

 swelling out and rounded at the fore 

 extremity, tail very short and pointed ; 

 colourless. Motor filaments above t^nce 

 the length of the body. Movements 

 slow; but rotation on the longitudinal 

 axis rapid. Several phases of Euglena 

 viridis resemble this species in form, 

 molecular arrangement of contents, size, 

 and motion, and are peculiar only on 

 account of their green colour and red 

 stigma. Ehrenberg remarks that they 

 are often so abundant that thousands, 

 perhaps millions, of these creatures are 

 sometimes contained in the hollow of a 

 watch-glass, and form a stratum on the 

 surface of the w^ater. They might be 

 mistaken for the young of the A. fia- 

 vicmis, but that the vesicles within them 

 are larger than those in that species, 

 which is, moreover, without proboscis. 

 As soon as a little colouring matter was 

 thrown into the water, an evident cur- 

 rent was observed near the fore part of 

 the creature ; and by this means, in 1833, 

 the thread-like filament, which is about 

 half the length of the body, was first 

 perceived. Sometimes the entire crea- 

 ture appears to glisten. Shoidd this 

 species, upon closer inspection, be found 

 to be ciliated, it would be rightly placed 

 among Peridiniaea. 1-1440" to 1-500". 

 The size of the vesicles remarked by 

 Ehrenberg is no distinctive character; and 

 Mr. Carter believes that both this species 

 and A. Jlavicans are either identical with 

 or very nearly allied to A. limpida, and 

 therefore animal organisms, unlike the 

 EiajlencB, to which they have a generaF 

 resemblance. 



A. (?) viridis. — Extensible ; of an 

 ovate-oblong form, distended a little at 

 the middle ; tail very short and pointed ; 

 green. Amongst Confervas. 1-1200" 

 to 1-900". This species and A. h(pma- 

 todes are, in Dujardin's opinion, members 

 of the genus Euyloia, the only appre- 



ciable diiference between them being the 

 presence of a red stigma in this genus. 

 In this opinion Mr. Carter coincides. 



A. nivalis (Vogt) (x^^I. 532-533).— 

 Oval, extremities roimded, rarely pear- 

 shaped, colour deep reddish-brown, mo- 

 tion rapid. Found with Protococcus ne- 

 hulosus in snow (Switzerland). 1-1500". 

 M. Vogt, in liis accoimt of the Astasia 

 nivalis, describes it as invested with a 

 carapace (lorica), open only at the an- 

 terior extremity. This opening is fur- 

 nished with numerous small cilia ; and 

 here, doubtless, the mouth is situated, 

 the indication of which is given by an 

 orange-coloured tint, which is clearer 

 than that of the rest of the animal. 

 "The presence of a lorica and cilia 

 affords a character which does not 

 allow this animalcule to be placed with 

 Astasia, as Shuttlew^orth has done; on 

 the contrary, it ought to be placed in 

 the family Peridiniaea (Ehr.), or else be 

 regarded as the type of a new genus, 

 distinguished by the absence of a groove 

 in the lorica, and by the stiff" hairs of 

 Peridinium being replaced by soft cilia." 

 (On the Animalcules of the Red Snow, 

 Bihl. Univ. de Geneve, 1841.) This pre- 

 simied species is, in all probability, 

 nothing more than an encysted cor- 

 puscle, probably a species of Chlamy- 

 dococcus. 



A. Acus. — Hyaline, figure long-fusi- 

 form, acute at each end ; filament the 

 length of the body. 1-650". Berlin. 

 Under the head Astasia, Perty enume- 

 rates the following species ; but, as he 

 makes no distinction between Astasia 

 and Distigma, the generic appellation is 

 not quite equivalent to that used by 

 Ehrenberg. 



A. margaritifera (Smarda). — Remark- 

 able by its variability of form, or meta- 

 bolia, the contents appearing to be driven 

 from one part to another, filling and dis- 

 tending one portion, whilst the other is 

 left empty and contracted. Hyaline 

 granules (germs?) very distinct. At 

 periods it loses its filaments, and with 

 them its powers of swimming, when it 

 adopts a crawling movement. Two 

 clear spots occur near the base of the 

 filament, which is once and a half to 

 t\vice the length of the body: these 

 spots were called eyes by Ehrenberg, 

 who made them the distinctive feature 

 of a genus Distigma. In pond-water, 

 and even under ice, but not common. 

 A variety, much elongated and slender, 

 has been called Astasia Serpetituhis. 



