l.)U5.] NATURAL SCIENCES OF PHILADELPHIA. C)65 



DELAWARE VALLEY FORMS OF TRACHELOMONAS. 



BY T. CHALKLEY PALMER. 



The uniflagellate protozoa belonging to the genus Trachelomonas 

 are normally provided with intensely green chromatophores, a red 

 pigment-spot, a contractile vacuole and a hard, brittle, brownish lorica. 

 The lorica has a single aperture wherethrough issues the very long 

 flagellum. With the aid of this flagellum the monad swims rapidly in 

 an irregularly spiral course. Though habitually inhabiting the lorica, 

 the monad is able to squeeze through the very small aperture and to 

 swim naked; and almost any rich gathering of Trachelomonas will 

 show numerous individuals in this condition, wherein they are scarcely 

 to be distinguished, except by minute study, from species of the nor- 

 mally naked genus Euglena. Different species of Trachelomonas, 

 when without their loricae, are not at all recognizable. Specific dis- 

 tinctions, in short, are founded of necessity, in thi,s genus, on lorica 

 characters. 



These loricae, when heated nearly to redness on a cover-glass, still 

 keep their shapes, and show only a certain loss of transparency and a 

 considerable reddening of the originally brown color. The ability to 

 withstand a high degree of heat was taken by early students of the 

 genus as an indication of their silicious constitution. When, however, 

 these loricae are treated with acids, the hardness, brittleness and color 

 gradually disappear, and soon nothing remains but a thin, gelatinous 

 pellicle, which in turn is capable of gradual and complete solution in 

 hot nitric acid or in sulphuric acid and bichromate of potash. The 

 mineral matter they contain is, therefore, something other than silica; 

 and Klebs,^ among others, has stated that this mineral matter is, in 

 some cases at least, ferric hydroxide. The test to determine this point 

 is sufficiently simple. It is only necessary to burn the loricae 'on a 

 cover-glass, and to invert over a drop of a solution of potassium ferro- 

 cyanide containing a small addition of hydrochloric acid. In a very 

 few minutes the acid begins to dissolve the oxide of iron, and simul- 

 taneously ferric ferrocyanide deposits as a blue cloud around each of 

 the loricae. The writer has put to this test most of the loricae pertaining 



' Klebs, Untersuch. Tubing. Inst., I, 1883. 



