666 PROCEEDINGS OF THE ACADEMY OF [Sept., 



to the Delaware Valley species, and in every case the result was as 

 described.^ During this investigation numerous lorica^ were also 

 dried upon the cover-glass without burning, and examined for carbon 

 dioxide with hydrochloric acid. The result was negative in every 

 case. The lorica of T. piscatoris was included in these tests. The 

 supposition of Fisher,^ that these loricae are to a considerable extent 

 composed of calcium carbonate, is therefore still without confirmation. 

 The effervescence observed by Fisher, and attributed by him to carbon 

 dioxide, ma)^ be capable of another explanation. 



Reduplication in the genus Trachelomonas is usually, if not always, 

 accomplished within the lorica, and the act is followed normally by 

 the withdrawal of one of the newly formed monads through the minute 

 aperture. This operation has been observed frequently by students, 

 so that its apparent impossibility goes for nothing. The naked indi- 

 viduals already referred to are largely the product of this process. 

 Subsequently, but after how great an interval of time is uncertain, the 

 euglenoid form is lost, the body assumes the spherical or ovoid shape 

 proper to the species, and a new shell is secreted. Tliis process the 

 writer has seen in part. The individual was of the species T. hispida. 

 The shell was already outlined as a very tenuous layer of nearly invisi- 

 ble gelatin, to the* outside of which clung a dim halo of inert minutse. 

 But this soft and adherent condition was only transitory. The animal, 

 revolving tirelessly within the nascent, stationary shell, continued 

 without ceasing to brush and pat and feel all over the surface with its 

 wonderful flagellum. By degrees the debris was mostly dislodged. 

 Within two hours the lorica was beginning to take on a slight tint; it 

 had attained to a consistency, though the spines characteristic of the 

 mature shell were still almost invisible. Very suddenly the lorica itself 

 began to revolve with the revolving monad, and in a moment monad 

 and lorica were gone. 



It sometimes happens that after subdivision the withdrawal of one 

 of the monads does not at once follow. Loricae are to be seen, now and 

 again, with two monads, much pressed for room, and with flagellse mu- 

 tually interfering and working at cross-purposes. The course of the 



' These loricae are, therefore, altogether different from the silicious shells de- 

 scribed by the present writer in these Proceedings, 1902, and there placed tenta- 

 tively in the genus Trachelomonas. Some of those described and figured, and 

 a few among the large number of similar ones observed, were afterwards seen 

 in living but quiescent condition, and the indications are that they represent the 

 resting or encysted state of various Protozoa, some of which at least belong to the 

 Chromomonadina. It was, therefore, a complete error to refer them to the genu 

 Trachelomonas. 



^ Fisher, 1880, Proc. Amer. Soc. Micros. 



