STRUCTURE OF THE CILIARY COMB. 



247 



both in Invertebrata (for example in the rectum of the larva of the 

 cockchafer) and in Vertebrata, both in cold-blooded (TricJwmonas 

 hatrachm'um) and in warm-blooded animals, and especially in mam- 

 mals, as in the stomach of the pig and the intestine of the guinea- 

 pig. Nor is it to be denied that some of the forms in the human 

 intestine described as Cercomonas belong to this genus. 



After the observations which Stein has published concerning 

 Trichomonas latrachorum,^ some modification must be made in the 

 opinion hitherto held by all investigators in regard to the structure of 

 the lateral comb, so characteristic of this order. For this does not 

 consist of single short filaments in a row near each other, but of an 

 undulating membrane, the vibrations of which easily gave rise to the 

 idea of ciliary motion. Here I may mention the familiar spermatozoa 

 of the salamander, whose fringed edges were also long referred to the 

 possession of cilia. According to Stein, however, the definition of it 

 as an undulating membrane is not perfectly correct. It should rather 

 be said that the extremely soft body rapidly pushes out, one after 

 another, tooth-like or rounded processes, which together produce the 

 impression of a wave ceaselessly running from front to back, along 

 the margin of the body, or " as if this were provided with a toothed 

 undulating membrane." It is not easy to see how this conception 

 can agree with the fact that the apparatus in c[uestion also appears 



Fig. 123. — Trichomonas batrachorum (after Stein). 



in dead animals in the form of an irregularly waving margin, which, 

 as I further note, allows itself to be stained in toto. [This has 

 recently been stated by Blochmann^ in opposition to Grassi {loc. cit.), 



Lor. rit.. 



p. li 



DigitiieS'BfM^mhM- ' 



Bd. xl., p. 42, 1884. 



