612 



SYSTEMATIC HISTORY OF THE INFUSORIA. 



This genus is admitted by Perty, who places it in the family " Holophmna," 

 but, unlike Dujardin, beheves it to possess a mouth. 



Spathiditjm hyalinum (xxvi. 27). — 

 Oblong, lanceolate, hyaline ; thin and 

 almost membranous anteriorly, and ter- 

 minated by an oblique margin, along 

 which some small black nodules may be 

 seen. In pond-water, near Paris. The 

 Enchelys SpatJuda of Miiller would seem 

 to be the same species; but the Letr- 

 cophnjs Spathula (Ehr.) differs from it 

 in having a row of cilia on the ante- 

 rior margin, with striae on each side, 



and in receiving indigo in its stomach- 

 sacs. 



Perty, however, treats them as identi- 

 cal. Indeed, the marks of distinction 

 Dujardin would draw are certainly in- 

 sufficient to establish a specific differ- 

 ence ; since the absence or presence of a 

 row of cilia may readily be unobserved, 

 and the reception or non-reception of 

 indigo is very mucli a matter of manipu- 

 lation. 



Genus HOLOPHRYA (XXIV. 281).— Ovoid, oblong, or even cylindiical; 

 covered with ^ibratile cilia ; mouth anterior, directly truncated or terminal, 

 and without lip or teeth. In two species the mouth and anus have been seen. 

 Cilia disposed in longitudinal rows. In H. Ovum green granules and a posterior 

 contractile vesicle are observable ; self-division appears to be transverse in 

 H. discolor. 



In the system of Perty, Holophrya gives name to a family " Holophryina," 

 defined as having '' an anterior mouth, a posterior anus, and the surface 

 covered with cilia in longitudinal rows." It includes the genera Holophrya, 

 some species of Enchelys and S^athiclium (Duj.), LeucopJirys (E.). The two 

 species of Enchelys mentioned are E. Farcimen and E. Pupa ; the LeucopJirys 

 is the L. Spathula (Ehr.). 



Holoplirya is closely allied to Prorodon ; indeed its independence is very 

 doubtful ; for the only distinctive character between the two genera put for- 

 ward is, that the *' dental cylinder " is absent in the foimer ; but this is a 

 structural peculiarity not always very obvious to the eye, liable to be over- 

 looked, and of secondary histological importance. 



Holoplirya and the following genus, Prorodon, are included in Dujardin's 

 family Paramecina. 



HoLOPHRYA Ovum {Leucoplira hursata, 

 M.) (xxiv. 281). — Ovate, somewhat 

 cylindrical, extremities subtnmcate ; 

 granules green. Amongst Lemnse and 

 Conferva. 1-570" to 1-210". 



H. discolor (Trichoda horrida, M.). — 

 White, ovate, conical, subacute at the 

 posterior extremity ; cilia long and 

 scattered. Amongst Confervae. 1-240". 



This species Stein has noticed in 

 the encysted condition, surroimded by 

 a thick-walled cyst. Cohn, moreover. 



found the previous species, H. Ovum, in 

 the same condition. Instead of being 

 white, it is often colom-ed green by 

 chlorophyll. 



H. Coieps {Leucophra glohulife)'a, M.). 

 — Oblong, cylindi'ical ; rounded at both 

 extremities; whitish. 1-430" to 1-280". 



H. hrunnea (Duj.). — Brown, changing 

 from a cylindrical to a globular form 

 when filled with food, and also then 

 altering in colour. 



Genus PRORODOX (XXIV. 282; XXVIII. 8).— Is distinguished by the 

 directly tnincated mouth, and a cii'clet or cylinder of internal teeth. Body 

 covered with vibratile cilia. Digestive cells, an oral, and an anal outlet have 

 been demonstrated by coloured food. A long band-like nucleus, contractile 

 sac, and granules are seen in P. niveus. 



In the system of Perty, Prorodon constitutes a member of the family 

 Decteria, in company with Chilodon, Nassula, Hahrodon, and Cydograimm. 

 Hahrodon is annexed to this present family ; but Oyclogramma will be found 

 placed among the Trachelina, along with Chilodon and Nassula. 



