GENUS A MPHIMONA S. 281 



interpreted. Biitschli remarks that under a high magnifying power it exhibits a 

 granular formation, and is apparently homologous with the eye-like pigment-spot of 

 Euglena and other Flagellata, while in Stein's figures, unfortunately accompanied 

 by no descriptive text, the same initial (b) is set against it that is employed in a 

 neighbouring form Spumella guttula distinguished by the possession of a similar 

 granular pig-nent-band for the indication of a presumed oral furrow. -The pre- 

 sence of ingested food-matter within the substance of the parenchyma is figured 

 and alluded to by Professor Stein, and is probably incepted indifferently at all parts 

 of the periphery. The movements of this type are reported by Biitschli to be rapid 

 and uninterrupted ; in some minute examples, however, recently examined by the 

 author, the locomotion was observed to be weak, tremulous, and subject to constant 

 interruption. 



GENUS II. AMPHIMONAS, Dujardin. 



Animalcules of spherical, ovate, or irregular outline, plastic and change- 

 able in shape, attached posteriorly by a slender, non-contractile, thread- 

 like filament : flagella two in number, equal in length and character ; food 

 incepted at any portion of the periphery ; contractile vesicle and endoplast 

 usually conspicuous. 



Out of the three species of this genus enumerated by Dujardin, the one, 

 Amphimonas caudata, is referable to the genus Heteronema, while the other two, 

 A. dispar and A. brachiata, are exceedingly doubtful forms that might represent the 

 motile condition of various biflagellate types. The two new species here introduced 

 adapt themselves so well, however, to the broad characters of the genus as first 

 established by Dujardin, that it seems desirable, with some slight amendment, to 

 retain his generic title of Amphimonas for them in preference to constructing 

 a new one, which would otherwise be necessary. As here characterized, the 

 representatives of this genus correspond on the one hand with those of P/iysomonas t 

 from which they are to be distinguished by their possession of two equal-sized 

 flagellate appendages, and on the other with those of Deltomonas, which while 

 possessing similar flagellate organs, attach themselves bodily to the chosen fulcrum 

 of support without the intermedium of a filamentous pedicle. Perty, in referring a 

 single form to the genus Amphimonas under the title of A. exi/is, evidently associated 

 with Dujardin's generic group an interpretation closely corresponding with the one 

 here adopted. Diesing, in his ' Conspectus dispositionis familiarum et generum,' 

 has merged the several species of Hexamita of Dujardin in the genus Amphimonas^ 

 though upon what grounds it is difficult to comprehend, the animalcules of that 

 generic type being multiflagellate and, as hitherto recorded, free-swimming forms, 

 presenting no resemblance whatever to the fixed biflagellate monads now under 

 consideration. 



Amphimonas globosa, S. K. PL. XIV. FIGS. 55-59. 



Body subspherical, attached posteriorly by a slender, flexible, filamentous 

 pedicle, equal in length to about three times its own diameter ; flagella 

 "even, inserted close to one another in the centre of the anterior border, 

 twice the length of the body, vibrated in an irregular undulating manner ; 

 parenchyma hyaline, vacuolar ; contractile vesicles two in number, situated 

 a little behind the median line ; endoplast spherical, subcentral. Diameter 

 of body 1-2000". HAB. Pond water with Myriophyllum. 



The considerably larger size of this animalcule serves to distinguish it at once 

 from Physomonas sodalis with which, when first seen, it is perhaps liable to be 



