GENUS TRACHELOMONAS. 389 



It has quite recently been shown by Stein * that the animalcules of this genus 

 correspond essentially with those of Euglena, and from the representatives of which, 

 indeed, they are distinguished only by their possession of a variously shaped indurated 

 lorica. In accordance with the more recent researches of this authority, the three 

 Ehrenbergian genera, Lagenella, Chcetotyphla, and Chcetoglena must also be merged 

 with Trachelomonas, these several forms exhibiting merely slight modifications in the 

 contour of the loricae that possess simply a specific value. As first described by 

 Ehrenberg, the lorica, in both Chcctotyphla and Chcztoglena, is reported to be siliceous, 

 but is evidently, as in the more normal Trachelomonads, simply corneous, but at the 

 same time of an exceedingly brittle and almost shell-like consistence. Lagenella was 

 separated by Ehrenberg from Trachelomonas with reference merely to the neck- 

 like prolongation of the minute terminal aperture, but which may be variously 

 developed or even almost entirely suppressed in individuals of the same species. 

 While under ordinary circumstances the bodies of the animalcules of this genus are 

 entirely enclosed within their ovate or spheroidal loricae, their lash-like flagella only 

 protruding, it was originally observed by Perty, and more recently by Stein, that 

 under certain conditions they contrive to squeeze through the minute anterior 

 aperture, the extruded body under such circumstances presenting the aspect of 

 a normal Euglena. This feat, comparing the large size of the animalcule's body 

 with the minute diameter of the orifice of the lorica, appears, as remarked by 

 Stein, to be as difficult of achievement as the passage of the proverbial camel through 

 the eye of a needle. The various phases of this process as delineated by him, 

 and reproduced at PL XXI. Figs. 15 and 22, serve to demonstrate the almost 

 amoeboid plasticity of the endoplasm and overlying cuticle. In many species the 

 lorica is remarkable for its red or crimson hue, this tint, however, being conspicuous 

 only as concentrated at the periphery, where it appears as a brilliantly coloured 

 ring or band around the bright green endoplasm of the enclosed animalcule. 

 Multiplication through the liberation from the parent body of a multitude of minute 

 monoflagellate germs has been observed by Stein in several species of the genus. 



Trachelomonas volvocina, Ehr. PL. XXI. FIGS. 14-16. 



Lorica spheroidal, entirely smooth, aperture usually level with the 

 adjacent wall but sometimes produced so as to form a minute cylindrical, 

 projecting neck ; periphery presenting the aspect of an encircling crimson 

 ring. Length i-iooo" to 1-860". 



HAB. Fresh water, amongst Conferva. 



In one example of this species as figured by Stein, the tubular neck is produced 

 into the interior cavity of the lorica, which in consequence resembles in contour 

 the shell of the Foraminiferous genus Entosolenia ; reference to this abnormal form 

 will no doubt appear with the forthcoming descriptive text. In other figures, here 

 reproduced, the egress of the animalcule through the minute aperture of the lorica 

 and the liberation from the body of the parent of a swarm of monociliated germs 

 are depicted. 



Trachelomonas mgulosa, Stein. PL. XXI. FIG. 17. 

 Lorica spheroidal, resembling that of T. volvocina, excepting that its entire 

 external surface is finely wrinkled ; anterior aperture plane or slightly pro- 

 minent. Length 1-1080". HAB. Fresh water. 



Trachelomonas lagenella. Stein. PL. XXI. FIGS. 18 AND 19. 

 Lorica colourless, oval or elliptical, nearly one and a half times as 

 long as broad, the anterior and posterior extremities even, sometimes 



* ' Infusionsthiere,' Abth. iii., 1878. 



