Rhizopoda of England and India. 289 



Collodictyon, nov. gen. 

 Collodictyon triciliatum, n. sp. PI. XII. fig. 12. 



Pyriform, straight, or slightly bent upon itself, bifid at the 

 small extremity, presenting at the larger one an indentation, 

 from which spring three cilia. Structure transparent, cancel- 

 lated, composed of globular cells, with a strongly marked green- 

 ish granule here and there in the triangular spaces between 

 them. Locomotive, swimming by means of the cilia ; subpoly- 

 niorphic, flexible, yielding, capable of assuming a globular form 

 (/) or one more or less modified by the body it may iucept (c, 

 d,g); enclosing crude material for nourishment in stomachal 

 spaces, and ejecting the refuse, like Amoeba. Provided with a 

 nucleus and contracting vesicles. 



Hob. Fresh water, chiefly among Euglena and Infusoria of 

 that kind. 



Size. Length - f | T s t of an inch. 



Loc. Island of Bombay. 



Obs. The plastic nature of this infusorium, and its mode of 

 incepting food being like that of Amoeba (for it does not appear 

 to possess any oral aperture), induce me to think that it should 

 be placed among the Rhizopoda. Still it seems to have some 

 analogies with Bodo, Ehr. The curved form (e) approaches that 

 of the colourless Bodo found in bunches, but, of course, is very 

 much larger. If Collodictyon be a Bodo, then it is a large form 

 of the latter, as Anisonema is a large form of the diplociliated 

 Monad. Again, what Astasia limpida, Duj. (Trachelitis tricho- 

 phorus, Ehr.), is to Euglena, Collodictyon is to the cordiform, 

 triciliated, Euglena-\ike Infusoria, of which probably Polyselmis 

 viridis, Duj. (Hist, des Zooph. Infus. pi. 3. fig. 27) is one; that 

 is, Collodictyon is the animal and Polyselmis the vegetable form 

 of this Infusorium. Its generic name has been derived from its 

 plasticity and delicate cellular structure, which gives it a reticu- 

 lar or cancellated appearance ; and its specific designation from 

 the presence of the three cilia. In voracity it is so greedy that 

 it will frequently enclose part of a body which it is not large 

 enough to enclose entirely (g) ; that is also like Bodo. The 

 cellular spaces which pervade its body are uniform and globular, 

 not variable in size and polygonal like those of Actinophrys 

 Eichhornii ; otherwise it so far resembles this Rhizopod. I have, 

 not inserted the contracting vesicles in the figures, because they 

 are not to be found in my sketches, probably from their having 

 no fixed position. The bifid extremity, although like the com- 

 mencement of duplicative division, is, I think, a persistent cha- 

 racter. Although this infusorium is very common in the island 



Ann. Z$ Mag. Nat. Hist. Ser. 3. Vol.xv. 19 



