G Mr. H. J. Carter on the Development of Gonidia 



describe their form ; but here and there, that which I have stated 

 may be seen in those which are less active in their movements 

 than the rest. 



There are, however, certain peculiarities about the elongated 

 and spindle-shaped gonidia which it is desirable to notice, viz. 

 that one cilium appears longer than the other, and that while 

 the short one floats almost motionless backwards, so as to 

 appear as if it proceeded from the posterior extremity, the latter, 

 for the most part, keeps up a constant whipping-movement in 

 front which frequently renders it imperceptible. Both cilia 

 however appear to be of the same length, if we add the length 

 of the gonidium to the one which floats behind, and which is 

 concealed in the first part of its course by lying in contact with 

 or underneath the body of the gonidium ; both also appear to be 

 occasionally brought together anteriorly. There is also fre- 

 quently a kind of proboscis extended from the rostrum or beak 

 of the gonidium which moves incessantly, both in the ovate and 

 spindle-shaped forms, and seems to have a suctorial extremity 

 by means of which it fixes the gonidium to the glass, while the 

 floating cilium also appears to be provided with a similar power 

 and to exert it for detaching the gonidium, when so fixed, by 

 pulling it backwards, which it does with a peculiar jerk ; when 

 this little proboscis has been present, I do not think I have ever 

 observed the anterior or active cilium. 



After a while, perhaps some hours, the gonidia become sta- 

 tionary, and while they appear to be fixed by the proboscis men- 

 tioned, the long cilium floats motionless, or presents a languid 

 kind of whip-like undulation ; the latter then disappears, and a 

 day or two after, the gonidia both small and great, for there are 

 many sizes, as will presently be mentioned, are seen creeping 

 about the watch-glass (into which they were transferred for ob- 

 servation) under as active polymorphism as any amcebous cell 

 could present ; diffluent, digitated, and in the form of that beau- 

 tifully radiated figure called Adinophrys Sol (Ehr.) . They also 

 now present the " contracting vesicle,^^ as well as other vesicles, 

 which do not appear to alter their dimensions, but vary, like the 

 former, in distinctness with their change of position and the 

 varying form of the gonidium. After a few days' existence in 

 this state their polymorphism becomes very sluggish, they re- 

 main for some time under a slowly changing rhizopodous figure, 

 which is more or less common to all, and then disappear. 



Whether they germinate or not, I have not been able to 

 determine. 



Lastly, a development of transparent mucus which becomes 

 filled with vibrios and Bacterium termo (Dujar.), immediately 

 follows the elimination of the gonidia both in the gonidial cell 



