Macurtre—Wotes on Certain Actiniaria. eT 
fixed in platinic chloride four per cent. solution for twenty-four 
hours then transferred to alcohol and imbedded in the usual 
way. ‘The platinic chloride fixes the stain very well; and it 
had penetrated to the endoderm in the superficial parts, such as 
the tentacles, but it was mainly taken up by the epithelial cells, 
and did not show any details of the nervous system. 
An adult specimen hardened in four per cent. formaldehyde, 
and examined macroscopically showed the following arrangement 
of the mesenteries. In section through the gullet, there are alto- 
gether twenty-four pairs of complete mesenteries, including two 
pairs of directives ; from embryological considerations, it is obvious 
that every fourth complete pair of mesenteries from each directive 
must be a pair of primaries. The secondaries and tertiaries can 
be determined in the same way. 
Thus of the complete mesenteries there are :— 
Primary, six pairs. 
Secondary, six pairs. 
Tertiary, twelve pairs, making twenty-four pairs of com- 
plete mesenteries. 
Of incomplete there are :— 
Fourth cycle, twenty-four pairs. 
Fifth cycle, thirty-eight pairs, making sixty-two pairs 
of incomplete mesenteries, eighty-six pairs in all. 
In the lower half of the column, the mesenteries were the 
same, except for the fifth cycle, of which there were apparently 
only thirty-six pairs. All mesenteries, except the fifth cycle, bear 
mesenterial filaments. Ina large adult examined microscopically, 
there are in sections through the gullet :— 
Primary mesenteries, 6 pairs (2 directives) ; 
Secondary ,, 6 pairs ; 
Tertiary 9 12 pairs, making twenty-four pairs of 
complete mesenteries ; 
Fourth cycle, - 24 pairs; 
Fifth cycle, | - 24 pairs; 
making forty-eight pairs of incomplete mesenteries, seventy-two 
pairs in all. Lower down the number of fifth-cycle mesenteries 
was, as far as they could be counted, the same. All mesenteries 
bear mesenterial filaments, except those of the fifth cycle. 
SCIEN. PROC. R.D.S., VOL. VIII., PART VI. 3H 
