52 SYNOPTIC COLLECTION. 



near it is the "tooth" and the long tentacle-like organ 

 which is transversely striated. The mouth leads into a 

 tube and this to a digestive sac. 1 



The reproduction of the Noctiluca has been described 

 in detail by Cienkowski.' 2 This investigator maintains 

 that we have here two identical histological cells blending 

 and, therefore, that conjugation in the Noctiluca belongs 

 in the rank of such phenomena of blending as aim at an 

 accelerated assimilation, and that it stands in no relation 

 with the more specialized sexual process of reproduction 

 of the Metazoa. This view may certainly be questioned, 

 since the act of conjugation, upon which, according to 

 Cienkowski, the formation of swarmers seems to be in a 

 high degree dependent, if not a sexual act, is most proba- 

 bly the initiative process leading towards the more spe- 

 cialized sexual process of the Metazoa. 



While it is true that most of the Mastigophora have 

 only one nucleus, yet this one is not probably identical in 

 constitution with the simple nucleus of the Amoeba or 

 with the nuclei of a many nucleated Rhizopod, since con- 

 jugation between the zoons of the Mastigophora is the 

 rule rather than the exception, and this more constant 

 differentiation in the process of reproduction is doubtless 

 attended with a differentiation in the nature of the repro- 

 ductive organ. Associated with this specialization of 

 process and function there is also the structural differ- 

 entiation of a primitive digestive system, and of a more 

 or less stable body with its constant accompaniment, in 

 youth as well as in adult life, of a locomotive and prehen- 

 sile organ. For these reasons the Mastigophora ( Flagel- 

 lata) may be considered as more specialized organisms 

 than the Rhizopods. Although Bergh 3 has supported the 

 opposite view considering that the Rhizopods have arisen 

 from the Flagellata, nevertheless the burden of evidence 



1 Packard, Zoology, 1886, pp. 33, 34. 



2 Arch. f. mikr. Anat., IX, 1873. 



3 Morph. Jahrb., VII, 1882, pp. 272, 273. 



