62 M. Ehrenberg's Researches on the Infusoria. 



muscles and internal ligaments, having an arrangement and a 

 power corresponding to the external organs of locomotion. 



Besides these organs, he has also discovered in these animals, 

 others whose forms and functions appear to have no relation with 

 the systems just enumerated. These apparently superfluous or- 

 gans are of two kinds, the one of a glandular form, the other fila- 

 mentous. The substance of the former, seen through the mi- 

 croscope, appears to be very minutely granular; and that of the 

 latter is also granular, or rather homogeneous and transparent. 

 In both of them no internal cavity can be distinguished, though 

 many of them present a diameter quite large enough for their 

 display. Two of these bodies, of a globular or cylindrical form, 

 are placed immediately behind the oesophagus, at the commence- 

 ment of the intestine, and, where there is a stomach, immediately 

 behind it ; they are large and easily recognised in all the Rota- 

 toria. M. Ehrenberg regards these as two glands, because they 

 are intimately united with the intestines, without being coecums, 

 for they are never filled with nutritive matter, and they always 

 follow the movements of the intestine. Both are attached by 

 their anterior extremity to the internal surface of the abdominal 

 cavity, by means of a ligament, small like the finest filament ; 

 sometimes they shew a vesicle in their interior. At one time he 

 imagined these two glands, whose situation is exactly that of the 

 two coecums in the Daphnia, to be the pancreatic gland. He 

 never witnessed them filled with coloured nutritive matter, whilst 

 the coecums in the Daphnia are very soon coloured along with 

 the intestine, as may be easily seen by experiments made with 

 indigo. 



M. Ehrenberg regards the small bodies situated round the 

 pharynx in the rotatoria (see PI. I. figs. 8 and 9) as nervous 

 ganglions, because they are not intimately united, and because 

 they do not necessarily belong to any of the systems previously 

 enumerated. Many of these bodies send forth slender filaments, 

 which in their arrangement present no analogy, either with the 

 dichotomic course of vessels, nor with the muscles ; neither do 

 they contract as the muscles do, when the animal is in motion, 

 and do not present any thickening during their contractions. 

 Nor does it appear that these filaments can be vessels, although 

 in similar circumstances these also remain in a passive state ; 



