1914 1 Sharp: Diplodinium ecaudatum 61 



of which are present in my material and have been identified by me. 

 We have already noted the inadmissible procedure of Eberlein (1895) 

 in assigning the species D. caudatum Fiorentini to D. rostratum Fioren- 

 tini and then appropriating the name D. caudatum for a species of his 

 own. This species, D. caudatum Eberlein, I have not yet identified, 

 but for purposes of conformity to the code of nomenclature I propose 

 for it the name Diplodinium eberleini. Granted that this species, 

 Diplodinium eberleini, is valid, then the genus Diplodinium contains 

 up to the time of this paper eight valid species or forms, viz. : D. 

 maggii Fiorentini, D. bursa Fiorentini, D. dentatum Schuberg (Fio- 

 rentini emend.), D. denticulatum Fiorentini, D. ecaudatum Fiorentini, 

 D. caudatum Fiorentini, D. cattanei Fiorentini, and D. eberleini nom. 

 nov. 



My observations lead to the conclusion that D. denticulatum is 

 merely a variant form of D. dentatum and that D. caudatum and 

 D. cattanei are only forms of D. ecaudatum. In fact it is one of the 

 purposes of the present paper to show that D. ecaudatum Fiorentini, 

 D. caudatum Fiorentini and D. cattanei Fiorentini are forms of the 

 species whose lawful name is Diplodinium ecaudatum Fiorentini. To 

 this species (D. ecaudatum Fiorentini) I add three new forms to which 

 I have given the descriptive names D. ecaudatum forma bicaudatum, 

 D. e. forma tricaudatum, and D. e. forma quadricaudatum. Diplo- 

 dinium caudatum therefore becomes D. e. forma caudatum, and D. 

 cattanei, in accordance with facts w r hich will be given later, becomes 

 D. e. forma cattanei. These three forms ( D. e. forma ecaudatum, D. e. 

 forma caudatum, and D. e. forma cattanei), together with my three 

 new forms, constitute a complete series ranging from D. e. forma ecau- 

 datum without posterior spines up to D. e. forma cattanei with five 

 spines. Allowing for normal variations in details of structure, the 

 morphology of these six forms is identical, with the exception only of 

 the presence and number of these spines and the necessary differences 

 in the form of the posterior end w r hich their presence or absence 

 occasions. From all the other species of Diplodinium, however, they 

 differ considerably. These facts seem to warrant the placing of these 

 six forms in a single species, which in accordance with the rules of 

 nomenclature must be designated as Diplodinium ecaudatum, although 

 many of the individuals have from one to five ' ' caudal ' ' appendages. 



