1902.] 



'EiL SCIENCES OF PHILADELPHIA. 



791 



FIVE NEW SPECIES OF TKilCHELOMONAS. 

 BY T. CHALKLEY PALMER. 



American forms of the genus Trachehmona, (Ehr.) Stein 

 though ppavently not infrequent or wanting in vanety, seen, no 

 have been stndied with any great degree of enthusiasm. Tte 

 nnmber of recognized secies is small. Mo-over, .t is somewha^ 

 doubtful if known forms have been qu.le adequately d'^ ">P"='^«' 

 ad characterized. Since the days of Ehrenberg. al-. 'he ch-i- 

 cal constitution of the shells of Tr«.hel»nma> has been the theme 

 of a continued, though desultory, discussion. 



No attempt will be made, in this preliminary paper, to deal with 

 ,he "enu as'a whole, or to discuss the values of characters relied 

 upon for speciSc diagnosis. I. will suffice for presen purp^ to 

 X Tr«cLfo»o,ia.as established by Ehrenberg, together w.th the 

 ^me author's genera, Lagenella, ChoM^Ua .uA CA^.^ua a 

 rsattiling one genus, the TrackeU^non^. of Stem ai,d of m» 

 s„bse.,uent authorities. Neither is it necessary o e^tei here at 

 kn"h into the subject of the constitution of the lorica. Th. 

 matLis, indeed, by no means simple; and o«ta,»^y .t .s not »- 

 capable of being decided, as to every specie by a &« « h 

 chemical tests upon the shells of one or '^-''T^t.^n^^Z I 

 ChMmhla and Cludoglma were supposed by Ehienbe.g to De 

 ^Hctuf On the other hand laier investigator, have found 

 ntssMe'to dissolve, wholly or in part, the shells of certain of the«. 

 Cs in acids. I have no notion of calling in question the correct- 

 ness of anv of these observations at present. , u^ a. 



The lorica, however, in each of the five species now to be de- 

 scribed is completely silicified. If this had not been the case the 

 o lowing descriptions would not have been written now and m to 

 form- for these five were selected from among about twenty, al 

 Z2Z in a prepai-ation of diatoms that liad been strongly boiled 

 (oTsome time I a large volume of concentrated n.tric add, to 

 iVcnhad been added, lorn time to time, small pieces of potassium 

 chlorate. Moreover, subsequent experiment, showed that 



