GENETIC REPRODUCTION. 



91 



and the quiescent sporocyst states, the first yielding the essential and 

 specific form, are now found to obtain throughout the majority of the 

 Flagellata. Simultaneously with, and in many instances anterior to, the 

 publication of Messrs. Dallinger and Drysdale's researches, corresponding 

 phenomena had been observed and duly recorded by the present author in 

 relation with the representatives of the Choano-Flagellata or collar- 

 bearing section, and other more simply organized Flagellata. Like results 

 have also accompanied his more recent investigations, while confirmatory 

 evidence in the same direction is abundantly aff'orded in the magnificent 

 volume devoted to the illustration of the Flagellata generally, lately pub- 

 lished by Professor Stein. As examples of the persistence of the three 

 above-named characteristic phases in the group of the Choano-Flagellata, 

 reference may be more especially made to the systematic descriptions and 

 accompanying figures of such species as Salpingcuca aiuphoridiiim, S. fiisi- 

 formis, and Codosiga botrytis, in all of which the transitory amoeboid phase 

 is particularly remarkable. In all those Eustomatous Flagellata which, 

 like Phaais and Anisonema, possess an indurated cuticle, the assumption 

 of an amoeboid condition would not be possible, and the animalcule pre- 

 vious to encystment and spore development merely loses its flagella, and 

 assumes a quiescent state. In Etiglena and its allies, including Eiitrcptia, 

 the animalcules exhibit a transitory amoebiform, or, more correctly, a 

 gregarine-like repent state immediately preceding the process of encyst- 

 ment. With the representatives of the two last-named genera it is further 

 worthy of note that the initial condition of existence on emerging from 

 the spore is hkewise amoebiform and non-flagelliferous. Among the Choano- 

 Flagellata this earliest stage is simply flagellate or monadiform, there 

 being no trace of the characteristic collar, while in a larger series, including 

 the majority of the Pantostomata, such initial phase, in all but size, 

 corresponds essentially with the parent zooid. 



Sexual or Genetic Reproduction. 



Sexual reproduction in the broad acceptation of the term as belonging 

 to the propagative phenomena of the higher animals or Metazoa, or, as 

 up to within a comparatively recent date maintained by Balbiani and 

 others to obtain among the members of the higher Ciliate section of Infu- 

 soria, and in either case involving the concourse of true and independently 

 developed sexual cellular elements — ova and spermatozoa — remains, so 

 far as it concerns all or any members of the class or classes now under 

 discussion, entirely undemonstrable. Nor, the essentially unicellular nature 

 or value of the infusorial organism, as here advocated, being once firmly 

 and incontestably established, can a contrary verdict be anticipated ! 

 Notwithstanding, however, the apparently uncompromising verdict pro- 

 nounced in the foregoing sentence, it will presently be shown that these 

 Protozoic organisms, in essence if not in fact, fulfil a role of reproduction 



