GENUS DALLINGERIA. 



3IT 



Swimming among the ordinary triflagellate members of the species the 

 metamorphosed monads were observed to attach themselves to one of these, the 

 two then swimming off and becoming by degrees completely fused with one another ; 

 all the flagella were now entirely retracted, the conjoined bodies exhibiting first an 

 irregularly lobate or amoeboid aspect, and finally a quiescent encysted state. The 

 cysts thus formed, Fig. 39, were of an elongate-ovate or fusiform shape, and 

 apparently devoid of all structure. After an interval of from three to five hours 

 the cysts were seen to burst or collapse, releasing a cloud of exquisitely minute 

 spores, hardly appreciable, and then only as the most minute specks, under a 

 magnification of 5000 diameters. In five hours after their emission from the cyst the 

 sporular elements grew to the size and contour of the parent form, the first traces of 

 the characteristic lateral flagella having made their appearance as minute points at 

 the end of the first two hours, before any movements had commenced, and while 

 each individual appeared under the magnification quoted as but little more than a 

 mere elongate speck. The habits of the animalcule as related by Mr. Dallinger are 

 remarkable. When swimming it progresses through the water rapidly, in a direct 

 line or in graceful curves, arresting, however, or reversing its course abruptly at any 

 moment. On these occasions, one or both of the two lateral flagella are brought 

 into action, and extended in an arm-like manner in place of remaining closely 

 adpressed to the side with their free extremities trailing, as is more usual when 

 a straight uninterrupted path is pursued. In all these movements the animalcule 

 apparently exhibits a complete volitional control over the movements of these 

 flagellate appendages and in the determination of its course. 



The highly characteristic sedentary condition of the adult form remains to be 

 described. Like Hetcromita^ Anisoncma, and other Flagellata, this type, as already 

 mentioned, temporarily anchors itself at will to any chosen spot, its moorings, however, 

 being rendered doubly secure by the utilization, for this purpose, of the two lateral 

 flagella in place of the single gubernaculate one employed by the foregoing forms. 

 In this " anchored " condition the animalcule still exhibits vigorous movements, which 

 are of a most remarkable character. In Auisoncma, motion when at anchor consists, 

 in its most actively motile state, of a swaying to and fro of the body only, after the 

 manner of a pendulum. In DaUingeria, according to its discoverer, it takes the 

 form of a rapid springing up and down, much as in Hetei-oniita rostrata, the two 

 adherent flagella being thrown, on the return of the body, into two spiral coils, which 

 are once more relaxed by the upward spring. In the performance of these 

 evolutions the body describes in the course of its descent the arc of a circle, striking 

 with great rapidity and proportionate force, hammerwise, upon the point represented 

 by the outstretched limit of reach of the anchoring flagella. It is further afiirmed 

 that this hammering action is always manifested in presence of decomposing organic 

 matter, the blows being levelled against it with the apparent purpose of breaking up 

 this material, and evidently contributing to or hastening such a result. Should the 

 animalcule be found to possess an oral aperture, or other means of appropriating in 

 a substantial form the fruits of its Vulcanic labours, this interpretation of its move- 

 ments might be accepted, but in the absence of any such demonstration the author 

 is scarcely prepared to regard its reported pulverizing accomplishments as other than 

 fortuitous.* 



Experiments, conducted with great skill and care by Mr. Dallinger, in order to 



* In the accompanying illustration the letters a and b of Fig. 35 denote the positions succes- 

 sively maintained by a zooid with relation to its base of attachment, through the coiling and 

 uncoiling of the lateral flagella. By accident, the ruptured cyst discharging spores, Fig. 40, is placed 

 at the point upon which the body of the animalcule would strike on the full extension of the spirally 

 coiled appendage ; repeated blows delivered in this fashion would doubtless have the effect of breaking 

 the cyst and scattering the', spores in the manner indicated. It might be suitably suggested as an 

 alternative to the food-pulverizing interpretation arrived at by Mr. Dallinger, that the characteristic 

 movements of these animalcules are intimately connected with such an artificial liberation and dis- 

 tribution of these spores. 



