PROCEEDINGS OK SOCIETIES. 191 



from Mr. Kitton in preceding number of this Journal, animadvert- 

 ing on new species of Diatomac£B described by the former gentle- 

 man, and which has already appeared in the last number. 



Royal College of Surgeons, Hunterian Lectures on the 

 Invertebrata. By Prof. T. H. Huxley, F.R.S. (Abstract.) 



{^Continued from page 129.) 



Lecture III. — The jVIonerozoa include besides the Forami- 

 nifera and Protogenes, other forms in which there is a 

 marked advance in structure. The Amosbse generally, which 

 used to be classed as Rhizopoda lobosa, belong here, and 

 present a nucleus and contractile vesicle. Professor Huxley 

 doubts as to whether the contractile vesicle has a permanent 

 opening. The Amoebae multiply by fission, and also present 

 an approach to a sexual mode of reproduction. The Amoeba 

 becomes quiescent, and perhaps encysted, when the nucleus 

 splits up into several pieces, each of which becomes sur- 

 rounded by a definite mass of the parent Amoeba's sarcode 

 substance, and each when set free becomes a new and very- 

 small Amoeba. The next step onwards in structure is found 

 in the Gregarinse. These organisms are all internally 

 parasitic. No distinct cuticular membrance is to be traced 

 in normal individuals, but the outermost part of the jelly- 

 like substance of which the animal consists is denser than 

 the rest, more or less, and forms a sort of cortical substance. 

 The inner and more liquid material contains innumerable 

 coarse granules, and a clear vesicular body or nucleus. No 

 pseudopodia are ever extruded by these animals. They live 

 by imbibition, being continually bathed in a nutritious broth 

 formed for them by the animal they infest. They reproduce 

 by a breaking up into bodies called pseudo-navicul<e. These 

 pseudo-naviculce, which are formed by encysted Gregarinse, 

 give rise to Amoeba forms which become Gregarinse. One 

 Gregarina can alone produce pseudo-naviculce, at the same 

 time Professor Huxley considers that the analogies of this 

 process with the conjugation of Algse should be borne in 

 mind. It is noteworthy that the younger Gregarinse have 

 almost no granular matter, and are by far more active than 

 the larger specimens. The Poraminifera, with Protogenes, 

 Lieberkuhnia, &c., the Amoebae and the Gregarniae, form the 

 group Monerozoa. The Radiolaria form the second group of 

 the Protozoa. Professor Huxlev, in his voyage in the 



