124 



Genus, Gromia (Uuj.). 



Gromia socialis (Arch.). 

 PI. XX, figs. 7—11. 



Specific characters. — Very minute, often occurring socially ; 

 body bluish, granular, with a distinct, sharply marked, white 

 nucleus, containing a ?ninute, dark nucleolus ; pseudopodia 

 elongate, branched, slender, reticulosely incorporated with 

 each other, and often mutually with those proceeding from 

 other individuals, and showing irregularly shaped expansions, 

 and carrying along hi a slowish current minute opaque gra- 

 nules ; test hyaline, colourless, orbicular, or broadly elliptic. 



Measurements. — Diameter from about ttW" to tttto"- 



Locality. — A single pool only in Glen-ma-lur Valley, 

 hence as yet very rare. 



Affinities and Differences. — The minute size, hyaline test, 

 dense body substance, minute passage for the pseudopodia, 

 white nucleus (with its nucleolus), and social habit, clearly 

 mark out this form from other Gromise ; its distinction 

 from Cystophrys Haeckeliana have been pointed out, as they 

 seem to me, in a previous part of the present communica- 

 tion. 



On Imbedding Substances /or Microscopic Section. 

 By M. Foster, M.D., Fullerian Professor of Physiology. 



In Max Schultze's ' Archiv' (vol. clxiv) is a short paper 

 by Professor Klebs, in which that accomplished micro- 

 scopist recommends the use of strong glycerine jelly for the 

 purpose of imbedding objects previous to the preparation of 

 microscopic sections. I have tried this repeatedly, but 

 having failed to secure the advantages said to be gamed by 

 it, have fallen back upon the paraffin process, which, by the 

 bye, we also owe to Professor Kleb's ingenu^ity. As this 

 method does not seem very popular in England, and is, 

 morever, very badly described in Strieker's ' Handbuch,' I 

 venture to give a note of the details upon which success 

 in it mainly depends. 



The process is most useful with objects Avhich have been 

 hardened in chromic acid or alcohol, and which are intended 

 to be mounted in balsam ; but it may be applied advan- 

 tageously to objects of all kinds. 



