STRUCTURE OF HALIPHYSEMA TUMANOWICZII. 479 



from Jersey, not only a quantity of living specimens, but 

 subsequently others, carefully treated by reagents on the 

 spot according to my directions. 



I may confess, without offence to Mr. Kent, that I was 

 intent upon discovering in his Haliphysema evidence 

 of the syncytium and collar-bearing flagellate cells described 

 by Haeckel, which, I thought it possible, might have escaped 

 his observation. My inquiries Avere made on both living and 

 preserved specimens, and have led to the discovery of a very 

 interesting structure, which miglit at first sight be taken 

 to indicate that the organism was built up of many cells, and 

 was similar to a sponge. The structure, as described below, 

 is, however, essentially that of the Protozoa, and leaves no 

 doubt whatever in my mind that Haliphysema is to be 

 referred to that group. 



Whether there are isomorphs of Haliphysema constituting 

 the group " Physemaria," as suggested by Mr. Kent, and as 

 also asserted by Dr. E,. Hertwig, of Jena, in Hoffnian''s and 

 Schvvalbe's ' Jahresbericht,' vol. vii, second part, is a matter 

 which is clearly out of the field of discussion. 



It is certainly most desirable that these " isomorphs" 

 should be produced, as I earnestly hope that they will soon 

 be, by my friend Profesor Haeckel, or else that some kind of 

 explanation should be offered to remove the present puzzling 

 antagonism of the statements which have been made in 

 regard to Haliphysema and Gastrophysema, by Professor 

 Haeckel on the one side, and by English observers on the 

 other. 



1. Condition of the material studied. — The specimens 

 forwarded to me were in two conditions : firstly, several 

 living specimens sent in a large vessel of sea water; secondly, 

 specimens preserved in Jersey by Mr. Kent by placing 

 them first in a large quantity — half a litre — of one sixth 

 per cent, solution of chromic acid, from which, after a 

 lapse of twenty-four hours, they were removed to strong 

 alcohol. 



2. External test. — In PI. XXII, fig. 1, I have given a 

 drawing of the external test of a small specimen, magnified 

 135 times linear. The specimens sent to me were very 

 varied in form, some much more elongated than that figured ; 

 others with a more globose anterior region (like Gastro- 

 physema) ; others exhibiting a nodose series of enlargements 

 (polythalamous). The character and direction of the " 

 spicules and fragments of spicules used to form the test was 

 not the same in all. The first specimens which I received 

 closely resembled the Haliphysema figured by Haeckel in 



