Megaloirochaea.'] infusorial animalcules. 613 



not shown.) There are no anterior muscles, but three pairs of 

 posterior ones, which disappear near the rotatory organ ; there is 

 also a back and two lateral pairs. Several transverse vessels appear 

 connected with two anterior, lateral, longitudinal vessels, which. 

 Dr. Ehrenberg states, must arise from a vascular network near the 

 head, as in Hydatina. He has also seen two spiral bands (gills), 

 situated posteriorly. Two beautiful red vi^ual organs lie immedi- 

 ately beneath the wreath of cilia, and behind them little oval 

 nervous ganglia. In the foot-like tail are two large wedge-shaped 

 glands, probably male organs. These creatures will feed upon 

 carmine and indigo, but are mostly filled with a golden-coloured 

 food. Fig. 370 represents a cluster of animalcules magnified, about 

 ten diameters, of which figs. 365 to 368 represent a portion, highly 

 magnified ; the first is an under view, the two next doi'sal views, 

 and the last a side view. Fig. 369 shows the jaws, teeth, and part 

 of the cesophagus-bulb separate. Sizel-60th; sphere 1-9 th. 



Family.— MEGALOTROCHAEA. 



No envelope or lorica ; rotatory organ simple, incised, or flexuose 

 at the margin ; it constitutes the purveying and locomotive appa- 

 ratus. Distinct muscular bands are seen, which can change the 

 shape of the body. In Megalotrocha, the alimentary canal is pro- 

 vided with two jaws, a stomach, two coeca, and two pancreatic 

 glands. In the other genera, it is a simple canal, without stomach 

 and coeca; Microcodon has two single-toothed jaws, but no pan- 

 creatic glands ; and Cyphonautes is toothless. The ovarium in all 

 the genera developes a few large ova. In Megalotrocha, the ovum 

 is attached to a thread ; vessels and tremulous gills are observed in 

 that genus ; organs of sensation are indicated by the red eyes in 

 two genera ; in the third, a ganglion is seen in their place. In Mega- 

 lotrocha radiating nervous ganglia, analogous to a brain, and four 

 dark glandular spheres, in the neighbourhood of the mouth are seen. 



The genera are thus related : 



Eyes absent Cyi'lionaiites. 



f one eye Microcodon. 



L two eye 



Eyes present 



yes Megalotrocha. 



