544 



SYSTEMATIC HISTOKY OF THE INFUSORIA. 



with a double filament. Are free and provided with an eye-speck, tail, and 

 double filament. The only known species is of a very beautiful green colour, 

 and has numerous transparent vesicles within it. A distinct, hyaline nucleus 

 is perceptible in the centre of the animalcule. Self- division of the contents 

 into four or more segments has been observed to take place, also propagation 

 by microgonidia. Schneider and Perty conciu* respecting the propriety of 

 detaching Chlorogonium from the Astasisea. Numerous dull-red specks are 

 scattered throughout its green contents, no one of which has the clearness 

 and distinctness of the stigma of Euglence. The primordial envelope, with its 

 enclosed green contents, varies in figure ; but not the external one, which is 

 rigid. 



Chlorogonium euchlorum (xviii. 

 47 ; XX. 15-21). — Spindle-shaped, verj^ 

 pointed at both extremities ; tail short ; 

 colour sparkling green. The eye-speck 

 is so delicate that it may be easily over- 

 looked ; but when the creature is dried 

 upon a plate of very clear glass, both the 

 eye and the double filament are readily 

 seen, and it may be preserved as a per- 

 manent microscopic object, x^aii. fig. 

 47 represents a cluster of six, each with 

 its double proboscis. In water-butts, on 

 ponds, &c. ; it forms the green matter of 



Priestley. 1-110' 

 of the tail. It was in this species that 

 M. Weisse thought he had discovered a 

 form of propagation analogous to that by 

 ova, but in fact to reproduction by mi- 

 crogonidia (xx. 15-21). The young 

 forms so produced, especially in their 

 aggregate state before discharge, re- 

 semble JJvella Bodo\ and M. Weisse 

 thinks Chlorogonium eiwklorum and 

 Glenomorum tingetis only other stages of 

 development of the same organism. 



Genus COLACIUM. — Eye-speck or stigma single. Filament not detected 

 in this genus, although, as Ehrenberg remarks, there can be no doubt of its 

 existence, from the currents which are \dsible in coloured water near the 

 forepart of the body ; still, as these are rather feeble, it is probable that the 

 organ is but single. Numerous transparent vesicles are seen within the body. 

 The creatures are parasitical upon Entomostraca and Rotatoria, to which they 

 attach themselves by means of a pedicle or footstalk, which is single at fii-st, 

 but becomes ramified by the process of self- division. 



Found upon Entomostraca. 1-860". 



CoLACiUM (P) vesiculosum. — Spindle- 

 shaped, oval, but variable ; pedicle very 

 short, and seldom ramified; colour 

 sparkling green, with distinct internal 

 vesicles. Ehrenberg says, " I have again 

 sought in vain for the red eye (May 23, 

 1835), but cannot be satisfied of its uon 



upon 



C. stentorinum. — Form variable, but 

 somewhat cylindrical, prolonged anteri- 

 orly into a funnel-shaped process ; colour 

 beautifid green ; vesicles indistinct; pedi- 

 cle often ramified. The eye-speck is at 

 one time distinct, at another scarcely 



existence, as it is imdoubtedly present perceptible ; it differs also in position so 



in the other species, and investigation 

 is sometimes improductiAe on account 

 of subordinate circumstances. I have 

 likewise failed in seeing very satis- 

 factorily the vibratory organ, notwith- 

 standing its action is evident enough." 



widely that sometimes it is close to the 

 elongated neck, at others near the poste- 

 rior end. Perty siumises it to be a larval 

 condition of some other being, or merely 

 a sporozoid. Found upon Entomostraca 

 and Polyarthra trigla. 1-1150". 



Genus DISTIGMA. — Astasice_ with two eye-specks. Locomotive organs 

 not hitherto discovered ; and the presumption is that they do not exist ; none 

 of the species either s^vim or produce perceptible cuiTents in coloured water. 

 Movements creeping or crawling, much like those of eels ; form variable, like 

 that of Lacrymaria; and they approximate to Amoeba in other respects, 

 besides the absence of a flabellum. At the fore part of the body may be 

 seen two very delicate, blackish -coloured spots, analogous to the eye-specks 

 in other genera. The Distigmo' are sometimes confounded ^^dth Vrotevs 



