OF THE CKYPTOMONADINA. 511 



T. granulata.— Similar, but its surface I tween tlie surface of this and the two pre- 

 very minutely granulated. I ceding are too trivial to be characteristic. 



T. /^m.— Globose, with its surface I T. pyrinn. — Oblong or pear-shaped 

 smooth. The assigned differences be- I (pyiiform), smooth, 



Dujardin, in his family Thecamonadina, includes some genera of animalcules 

 not described by Ehrenberg, or described by him under different names and 

 according to a different arrangement. They are appended here as best agree- 

 ing with the Cryptomonadina. 



Genus PHACUS (D.). — Body flattened, leaf-like, and mostly green. It 

 displays a red speck in front, together with a flagelliform filament ; and the 

 resistant membranous integument is prolonged posteriorly in the form of a tail. 



'' Three out of the foiu' species are referred by Ehrenberg to his genus 

 Euglena, on account of similarity in colour. The difference between the two 

 genera is, however, considerable ; for in Euglena the integument is contractile, 

 and pennits of a frequent change of form, whilst in Pliacus, on the contrary, 

 the integument appears quite wanting in contractility, and the animal inva- 

 riable in form. 



" The enclosing integument of Phacus persists after the death of the animal 

 and the destruction of the contained green mass, and also after the action of 

 various chemical agents, becoming, in the latter cases, quite transparent. 

 The motor fflament disappears with the living contents; globules of the 

 latter remain after death." 



Mr. Carter (A. N. H. 1856, xviii. p. 241) describes a single, glairy, discoid, 

 capsuled body in the centre of Pliacus, as well as in the large lip of Crume- 

 nida texta. 



1. Phacus pleuronecteszzzEiiglena pleuronectes ; 2. PAongicauda=^E.longi- 

 cauda ; and 3. P. triquetra = E. triquetra. (See Euglena.) 



The new species, of which the characters are given, is 



Phacus tripteris. — Oblong, with 

 three longitudinal plaits meeting along 

 the axis, rather twisted on the midrib, 



with a red speck in front and a dia- 

 phanous caudiform prolongation behind. 

 1-420" to 1-312". 



Genus CEUMENULA (D.) (XXVI. 6).— Oval, compressed, covered by a 

 resistant iategument (testa) apparently reticulated, sending out a long flagelli- 

 form filament obliquely from a notch in the anterior border. Motion slow. 

 There is no tail-like prolongation, as in Phacus. A contractile vesicle present. 



CnuiiENULA texta. — Envelope re- ! pointed sigmoid fibres ai-ranged parallel 

 ticular, filled with a green matter, toge- I to each other, so as to form a conical 

 ther with vacuoles or hyaline globules, ' cell, which remains behind when the 

 and having a large red globule anteriorly, j softer contents have dispersed. 

 1-520". Testa persistent after death. The anterior notch is produced by a 



In this species Mr. Carter {op. cit. sort of overhanging lip. The filament 

 p. 119) describes an inner layer of ! is three times longer than the body. 



Genus DISELMIS (D.). — Ovoid or globular, covered by an integument, not 

 contractile, of almost gelatinous consistence ; two equal locomotive filaments 

 proceed from the anterior extremity. 



" This genus nearly corresponds to the Chlamydomonas of Ehrenberg, placed 

 by him in the family Volvocina by reason of its apparent self-division into 

 two or foiu" segments within the testa. Dujardin, on the other hand, admits 

 none as Volvocina which do not exhibit an aggregation of perfect individuals 

 withia a common envelope." 



The removal, by Dujardin, of the Chlamydomonads described under this 

 name of Disehnis, from Volvocina to Crj^ptomonaduia, is generally held to 

 be an error, dependent on an imperfect conception of their characters and 

 true affinities. (See genus Chlamybomonas.) 



