338 DESCRIPTION OF [Rotatoria. 



Family XXV.— MEGALOTROCHAEA 



Have no envelope or lorica, but possess a simple rota- 

 tory organ, incised or flexuose at the margin ; this consti- 

 tutes the purveying aud locomotive apparatus. 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 pan- 

 creatic glands. In the other genera, it is a simple canal, 

 without stomach and coeca; Microcodon has two single- 

 toothed jaws, but no pancreatic glands ; and Cyphonantes 

 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 other, a ganglion is seen in their 

 place. In Megalotrocha radiating nervous ganglia, similar 

 to a brain, and four dark glandular spheres, in the neigh- 

 bourhood of the mouth, are seen. 



The genera are thus related : — 



Eyes absent Cyphonantes. 



Eyes present 



r one eye Microcodon. 



L two eyes Megalotrocha. 



Genus CXL. Cyphonautes. The hump-hacked Ani- 

 malcules are destitute of eyes. Locomotion is performed 

 by the continuous but notched cilii wreath and an internal 

 band-like muscle. The nutritive apparatus consists of a 

 toothless oesophagus, an alimentary canal, with probably 

 a pancreatic gland; an ovarium, M^ith a single large ovum. 



