Hydatinaea.'] TH E INFUSORIA 353 



glands, and a contractile vesicle. The vascular system is 

 indicated by many parallel transverse circular canals, and 

 a large tremulous organ, similar to a gill, near the con- 

 tractile vesicle. A brain-like knot, situated near the 

 oesophagus, sends off a thick tortuous thread along the 

 dorsal surface to the second transverse vessel, where the 

 respiratory opening probably exists. Posteriorly, near the 

 alimentary canal, is a dark granular organ, whose function 

 is unknown. 



581. ENTEROPLEA hydatina. The crystalline Enteroplea. 

 Body conical, transparent, with a little forked foot. 

 Anteriorly, four longitudinal muscles reach to the middle 

 of the body, and one dorsal, one ventral, and two opposed 

 lateral ones, are also seen. Two internal short wedge- 

 shaped muscles move the pincer-like foot. Ehrenberg 

 counted ten or eleven circular canals in the vascular system. 

 This animalcule is always smaller than Hydatina senta, 

 which it greatly resembles. Fig. 393 represents this ani- 

 malcule, in which the internal parts, named in the generic 

 description, are shewn. Length 1-1 20th. 



Genus CL. HYDATINA. The crystal Animalcules are 

 destitute of eyes, but have two many-toothed jaws 

 (fig. 383*) and a fork-like foot ; locomotion is effected by 

 the compound wheel organ, the pincer-like foot, and in- 

 ternal muscles ; the latter are most numerous in H. senta. 

 The alimentary canal has a globose oesophagal head, with four 

 muscles and jaws, and with two to five teeth. In H. senta 

 the jaws are connected by a short oesophagus to a simple 

 conical alimentary canal ; in the other species, to a con- 

 stricted one ; the large anterior extremity has two spherical 

 glands. The ovarium is globular. Two thin wedge-shaped 



2 A 



