Sharp: Diplodinium ecaudatum 103 



ADDENDUM 



This paper was accepted for publication by the University Press, 

 May 10, 1913. The receipt of a very generous gift. May 22, 1913, 

 made possible the publication of plate 4 in colors and also the addi- 

 tion of the microphotographs, plates 6 and 7. The preparation of 

 these plates has delayed publication. 



On December 12, 1913, after this paper had gone to press, the 

 Archiv fiir Protistenkunde, of November 11, 1913, containing Braune's 

 excellent paper, ' ' Untersuchungen tiber die im Wiederkauermagen 

 vorkommenden Protozoen, " was received at this laboratory. Since 

 Braune has worked on the same family, the Ophryoscolecidae, as 

 myself, and has figured and described for Opkryoscolex purkynjei 

 Stein structures which are apparently homologous with those described 

 by me for Diplodinium ecaudatum, and since our interpretations, not 

 only of the morphology but also of the functions of several of these 

 structures, differ to some considerable extent, it seems necessary to 

 add a word here. It must be kept in mind that although our observa- 

 tions have been made upon somewhat similar organisms, yet notwith- 

 standing their close relationship these organisms may present many 

 dissimilarities. Having made no comparative study of the minute 

 structure of the form which Braune describes I must content myself 

 with a brief discussion of the more obvious points wherein we differ. 



Although the distinction between ectoplasm and entoplasm may be 

 a more or less arbitrary one depending upon the definitions of the 

 observer, still the separation by Braune (1913, p. 151, and pi. 6, figs. 

 38-41) of the " Ectoplasma, " " Grenzschicht, " and "Entoplasma" 

 of Schuberg (1888), Eberlein (1895), and Giinther (1899, 1900) into 

 his so called "Entoplasma a," " Fibrillenschicht, " and "Entoplasma 

 b" is not in harmony with the evidence obtained by me from Diplo- 

 dinium ecaudatum. Nor is it altogether in accord with Braune's own 

 work, for he suggests (p. 152) the correspondence with similar layers 

 in Isotricha prostoma and yet in this form both in his description (p. 

 140) and in his figures (pi. 5, figs. 32, 33) he holds that the ciliary 

 roots penetrate only as far as the "Grenzschicht" which separates 

 ectoplasm from entoplasm while for Opkryoscolex purkynjei, he states 

 (p. 158, pi. 6, fig. 37) that the membranelle roots pass through not 

 only the ectoplasm and ' ' Grenzschicht, ' ' but also penetrate the ' ' Ento- 

 plasna a." 



