530 DEscEiPTiON OF \Tolygastrica. 



hour ; for on the approach of any foreign body to one, it withdraws, 

 by coiling iij) its i^edicle, while the others remain stretched out in 

 search of food. The pedicle is not contracted, but merely deflected, 

 by means of the long muscle within it, so that it can form as many as 

 ten coils, like the spring of a bell. The body of the animalcule does 

 not contract or become wrinkled, but the ciHated margin appears 

 sometimes bent inwards. In colour, when seen in masses about the 

 roots of Lemna, they appear ■\\diite. An amplification of 300 diame- 

 ters is necessary to exhibit the cilia. Longitudinal self- division may 

 often be observed, during which the body becomes broader. Gemmae, 

 or buds, shoot out from the sides of the other species, but have not 

 been noticed in this. Found abundantly on the stalks of Lemna and 

 other water-plants, even in winter under ice. Length of body 

 l-570th. to l-280th. 



YoKTicELLiNA citrina (M.) — The body is more hemispherical than 

 the preceding, and the frontal margin more expanded. Found upon 

 Lemna, rarely with the former species. Length of body 1 -430th. to 

 1-2 10th. ; stalk three to four times that length. 



V. microstoma. — Has an ovate body, attenuated at both ends, and 

 having the frontal margin narrow, not expanded. The body, during 

 contraction, is annulated ; its colour whitish-grey. The mouth, 

 stomach, reception of coloured food, male glands, ova, and long 

 muscle of the stalk, have all been observed in this species, as also 

 spontaneous longitudinal and transverse self-division, and the 

 gi'owth of gemmae. Ehrenberg counted from twenty to twenty-four 

 cilia in the frontal wreath. Found in stagnant water. Length 

 of body 1 -2300th. to l-240tli. ; length of stalk six times that of 

 the body. 



V. campanula ( Vorticella lunaris, M.) — Body hemispherical, bell- 

 shaped, with the frontal margin broad and truncated ; not expanded. 

 Colour whitish-brown, (ring, none.) This species forms a tliick 

 blucish matter upon water-plants, and the single animalcules are 

 discoverable with the naked eye. Size l-120th. ; stalk seven times 

 longer than the body. 



V. hamata. — Body small, ovate, hyaline, attenuated at both ends ; 

 pedicle oblic^uely attached to the body, so as to foim something of a 

 fith-hook appearance. Length of body l-570th. 



