598 



SYSTEMATIC HISTOEY OF THE INFUSOEIA. 



CcENOMORPHA ^ledustdci (XX\^II. 27- 

 30). — Colourless, transparent, ^dth a 

 small number of internal vesicles and 

 molecules. Lenglb tog-ether with the 



tail, 1-240" to 1-190". It s^\^ms actively 

 and rotates on itself, undergoing various 

 changes in outline. Some specimens ex- 

 hibit folds of the surface. 



Genus 8PIR0CH0NA (Stein) (XXX. 17-20, 27, 28).— Body naked, but 

 having a firm corneous integument ; attached perpendicularly by its base, 

 and quite motionless ; of an elongated, flask-like shape, with an anterior, 

 spirally-convoluted, funnel-like head or peristom. Posteriorly it narrows to 

 a small base, whereby it is fixed either immediately or mediately by a very 

 short pedicle. The infundibiiliform spiral peristom surmounts a constricted 

 portion or neck. The sj^iral lamina forming the peristom terminates abruptly 

 below, so as to leave a cleft, which conducts to the mouth ; its upper portion 

 is roUed around the longitudinal axis of the peristom, and produces a solid 

 central pivot. The innermost turn of the lamina constitutes a funnel, which 

 siu-mounts the whole peristom, and with the next coil forms what Stein calls 

 the " spiral funnel," whilst the lowest and widest spiral represents the true 

 peristom, homologous with the ciliary spii^al or peristom of Vorticella. The 

 latter is richly covered vdth cilia, which extend in less number to the second 

 coil. Internally, a digestive tube is seen to extend a considerable distance 

 from the mouth, having a contractile vesicle placed near its termination. A 

 large nucleus is seated near the middle of the animal, having a clear central 

 space or nucleolus. Fission has not been witnessed ; but gemmae are fre- 

 quently produced, which, under certain cii'cumstances, become encysted, and, 

 as Stein believes, undergo an Acinetiform metamorphosis (XXX. 21-28). 

 Length 1-750" to 1-216"; breadth of largest 1-600". 



^'PiROQ^o^x c/emmipara (xxx. 17-20). 

 ■ — The above description applies spe- 

 cially to this form. Found on the ova- 

 eapsides of Gammarus and other Ento- 

 mostraca, in fresh water. 



Sp. Scheutenii (xxx. 27, 28) agrees 

 with the foregoing in size and figure ; 

 but the peristom is more simple, consist- 

 ing of little more than a single coil of a 



wide lamina, and has, besides, a series of 

 stifi" fibrous processes fringing it on one 

 side. The internal face of the funnel is 

 lined with cilia below. Found on Ento- 

 mostraca in brackish water near Am- 

 sterdam by M. Scheuten; they are at- 

 tached to the long feathery bristles of 

 the post-abdominal feet, and not to the 

 ova-capsules, like S. gemmipara. 



FAMILY lY.— OPHEYDINA (VAGINIFERA). 

 (XXYII. 10-15 ; XXYIII. 18-20, 23 ; XXX. 29-35.) 



Loricated polygastric animalcules, solitary or aggregate, possessing a distinct 

 alimentary canal, a separate mouth and discharging orifice, which approxi- 

 mate and terminate in the same spot. In organization it resembles the 

 family Yorticellina ; in fact, continues Ehrenberg, it includes true Vorticellce 

 or Stentors, enclosed in a gelatinous, membranous, combustible lorica. Be- 

 sides the usual frontal wreath of cilia, there is in OiDhrydimn a second wreath 

 placed posteriorly ; and Tintinnus has an clastic muscular stalk or tail. Al- 

 though, as Ehrenberg teUs us, the pol3^gastric organs of nutrition can be 

 demonstrated in all the tribe by using coloured food, it is only in Ophryd'mm 

 that an alimentary canal has been distinctly seen. Longitudinal division of 

 the body takes place within the lorica, which continues unaffected. In 

 Ophrydium transverse division has been doubtfully affirmed. 



The genera are disposed as follows : — 



