330 PROFESSOR ALLMAN. 



more fully by Cienkowski.^ It is probable, however, that 

 the nucleated cell-like bodies which are present in the peri- 

 pheral layer of protoplasm have a reproductive function and 

 are destined after liberation to become developed into new 

 individuals. Huxley notes the presence of '^ granular vesi- 

 cular bodies of about 2-0V0 of an inch in diameter scattered 

 over the surface of the anterior and inferior part of the body,"^ 

 and regards them as possibly belonging to the reproductive 

 apparatus. These would seem to be the bodies which Cien- 

 kowski has seen to become transformed into swarm spores. 



From the account now given it will be seen that Noctihica 

 is destitute of all trace of a contractile vesicle, and that no cilia 

 are developed on any part of its surface. It consists, in fact, 

 essentially of an enormously vacuolated protoplasm involving a 

 nucleus and enclosed in a structureless sac, which is provided 

 with an inferent and probably also with an eferent opening ; 

 the vacuolation taking place to such an extent as to separate 

 the contents into a peripheral layer of protoplasm which 

 remains adherent to the outer sac, and into a central mass 

 which is kept in communication with the peripheral layer by 

 processes of protoplasm which pass from one to the other in 

 the form of a meshwork of branched and intercommunicating 

 filaments. 



That Noctiluca constitutes a very aberrant type of the 

 great group of the Infusoria must, t think, be admitted. 

 From the typical Infusoria, however, it departs widely. The 

 absence of contractile cavity and of superficial cilia are 

 points in which this divergence is especially obvious. I am 

 scarcely disposed to view the nucleus of Noctiluca as repre- 

 senting the so-called nucleus of the typical Infusoria, and I 

 would rather regard it as corresponding to a true cell- 

 nucleus. Indeed, it is difficult not to see in Noctiluca the 

 essential characters of a cell wliich has reached a certain ad- 

 vanced stage of differentiation without losing its original unity. 

 Among the animals whose position among the Infusoria is 

 generally admitted are those belonging to Ehrenberg's genus 

 Peridinea. It is to these that I believe Noctiluca bears the 

 closest affinity, closer even than to Trachelius, whose affinity 

 to Noctiluca has been especially maintained by Gegenbaur. 

 In a little animal examined by myself many years ago,^ 

 and which comes nearer to Peridinea than to any other genus, 

 we have the internal protoplasm with a nucleus all enclosed 

 in a firm structureless external sac, while no trace of con- 

 tractile cavity could be detected in it. We have, further, 



> " Ueber Schwarmerbildung bei Noctiluca," ' Schultz's Archiv,' b. 7. 

 - Loo, cit., p. 54<. 2 'Quart. Journ, Mic. Soc.,' vol, iii, 1855. 



