10 



THE AMEIUOAI^ MONTHLY 



[January, 



tures so low in the scale of life should 

 at one time undergo a threefold, and 

 at another a four-fold, longitudinal 

 fission. One can scarcely believe that 

 their resources are so extensive, or 

 their intelligence so well developed, 

 that they can select so different a 

 method apparently at will. Congenial 

 surroundings and the presence or ab- 

 sence of suitable food might be sup- 

 posed to exert a controlling influence, 

 but when both species are found, as 

 I have found them, attached almost 

 side by side to the same Lemna root- 

 let, those suggestions seem to be of 

 but little value. 



As an appropriate designation for 

 those colonies whose main rachis dis- 

 tally supports three branches I would 

 suggest the name of the English writ- 

 er who has made a special study of 

 the charming members of the order, 

 and propose that the species be known 

 as Codosiga Kentii. 



It is an interesting fact that the pre- 

 vailing form in this country, if I may 

 judge from my own observations, is 

 the species with the quadripartite ped- 

 icel (Fig. 3, reduced from Kent), 

 while the other obtains in England. 

 In the little pond among the hills of 

 Western New York, where I first saw 

 them, the colonies occurred in abun- 

 dance. Scarcely a Lemna rootlet 

 came to the microscope stage without 

 being ornamented by their crystalline 

 arborescence, while the infinitesimal 

 flagella lashed the water into micro- 

 scopic whirlpools. Here the bi-tri- 

 partite species occurred so sparingly 

 in proportion, that those with four di- 

 visions to the main stem with four 

 branchlets to each formed ninety per 

 cent, of the whole. 



Since returning to my home in 

 Trenton, I have observed several fine 

 colonies of the quadripartite form 

 with not only the main stem but the 

 secondary branches as well, changed 

 from the almost colorless state to the 

 translucent brown tint. The altera- 

 tion seems to be a favorite one with 

 these exquisite creatures. Since then 

 also, other colonies have been taken 



which in 'some important particulars 

 resemble the quadripartite form of 

 C. umbellata^ but difler in others as 

 essential. The only way to be sure 

 that the observer is studying a mature 

 member of any genus of the Choano- 

 Flagellata is to witness reproductive 

 fission and the departure of the sepa- 

 rated moiety. This, I presume, was 

 accomplished by the discoverer of the 

 bi-tripartite form, or variety as he 

 considers it. But since Mr. Tatem 

 in 1868 described the quadripartite 

 footstalk as that of an Epistylis, it is 

 reasonable to suppose that he did not 

 witness the reproductive act, and that 

 he may therefore have had an imma- 

 ture form of even the quadripailite 

 colony beneath his objective. I am 

 led to this supposition because I have 

 recently obtained, near Trenton, col- 

 onies corresponding with the last 

 mentioned in proportionate length of 

 main rachis, in number and arrange- 

 ment of secondary branches, and in 

 the number of what would be the ul- 

 timate subdivisions of the latter ; that 

 is, corresponding up to those points 

 at which the zooids would appear and 

 be supported, but having those sub- 

 divisions, or branchlets, still further 

 divided, where each, in those noted 

 by mvself, gives origin to four other 

 stalks which thus increase the height 

 of the colony and now act as the im- 

 mediate supports of the animalcules, 

 only two of the latter being attached 

 to each ultimate stem. The collared 

 infusorians correspond with those of 

 the quadripartite form, the pedicel of 

 which is depicted in Fig. 3, in shape, 

 size and internal structure, the whole 

 making, as I take it, the complete 

 and matui'e example of Codosiga um- 

 bellata. The compound footstalk of 

 this typical form is shown in Fig. 4, 

 where it has not been thought neces- 

 sary to delineate the collared monads, 

 as they are not absolutely essential to 

 the present purpose. 



My hypothesis is further sustained 

 by the fact that in Mr. Tatem's figure 

 of his supposed epistylis four zooids 

 are shown at the exti'emity of each 



