GENUS DALLINGERIA. 309 



points have to remain undecided, these relating chiefly to the character and number 

 of the flagella. In one instance as many as three, but in all others only two of 

 these appendages are produced from the anterior extremity. It is also somewhat 

 difficult to decide whether the so-called posterior flagellum is actually developed 

 from this region, or is merely a reflexed member of a single anteriorly inserted 

 series. 



Trichomonas vaginalis, Duj. PL. XIX. FIGS. 33 AND 34. 



Body irregularly ovate, tuberculate, soft and plastic, and changeable in 

 shape, often adherent by a gelatinous tail-like prolongation of the posterior 

 extremity of the body ; flagellum thicker at its base, fine and slender ante- 

 riorly, two or three times the length of the body, supplemented apparently 

 by a lateral fringe of large and conspicuous cilia ; endoplasm vacuolate. 

 Length of body 1-2500". HAB. Vaginal mucus. 



This species was first observed in decomposed human vaginal mucus by M. 

 Donnd, he communcating the circumstance to Dujardin. The zooids occurred in 

 aggregated groups or as isolated individuals which readily adhered to the glass 

 object-carrier, or other fulcrum of support, by a glutinous prolongation of the 

 posterior extremity, their movements when so attached being oscillating. It has 

 been suggested by some authorities that the objects thus observed by Donnd were 

 merely singly detached or agglomerated cells of ordinary ciliated epithelium ; the 

 possession, however, of a distinct flagellate appendage, as indicated in Dujardin's 

 drawings, would seem, pending further investigation, to justify its provisional in- 

 clusion among the members of the present organic group. Neither the diagnosis 

 here given of either this or of the succeeding species is to be accepted as complete, 

 they being constructed from the very imperfect descriptions and figures placed on 

 record by investigators who had not optical appliances suitable for their exhaustive 

 examination. With such assistance it will probably be found that, as in Trichomonas 

 batrachorum, the apparent lateral fringe of cilia is in reality an undulating membrane, 

 and that the single flagellate appendage hitherto observed is supplemented by others 

 of like kind. 



Trichomonas limacis, Duj. 



Body ovoid, smooth, pointed at each extremity; flagellum slender 

 throughout, about twice the length of the body ; a lateral fringe of cilia 

 apparently extending from the base of the flagellum more than half- 

 way to the posterior extremity ; endoplasm vacuolar ; movements active, 

 rotating on its axis. Length of body 11650". 



HAB. Intestinal tract of Limax agrestris. 



GENUS III. DALLINGERIA, S. K. 



(Nora, prop., Dallinger.) 



Animalcules free-swimming, more or less ovate, persistent in form, 

 having a single antero-terminal, and two oppositely placed lateral flagella, 

 the latter adhesive at their distal extremities, permitting the zooid to 

 temporarily anchor itself to any chosen spot after the manner of Heteromita 

 and A nisonema. Endoplast conspicuous ; no distinct oral aperture. Inha- 

 biting animal macerations. 



This new genus is established for the reception of the animalcule figured and 

 described by the Rev. W. H. Dallinger, in a memoir published in the ' Proceedings 



