354 HISTORY OF BRITISH ZOOPHYTES. 
that this might be the case, both to Dr. Fleming and Dr. 
Johnston, before I knew that the same suspicion had been 
entertained by persons of higher name. My attention has 
thus been directed to the subject for several years; and the 
result is, that I am now disposed to think that it is a dis- 
tinct species. It is exceedingly common with us; and JL. 
nitida, to which it bears the greatest resemblance, is, on the 
west coast, exceedingly rare. When richly studded with 
its pearly operculums, it makes some approach to L. ciliata 
when rich with opercula as the var. imsignzs (not rare with 
us) very frequently is; but the form of the cells is quite dif- 
ferent; and towards LJ. annulata it makes not the slightest 
approximation. 
11. Frusrra pistans, Hassall. 
Hab. On aquatic plants in brackish water. 
Considerably more than a year ago, specimens of this 
curious zoophyte were sent to me by Mr. Wigham, of Nor- 
wich, who stated that he had gathered it m abundance 
at Yarmouth, in ditches of brackish water, about a mile 
distant from the sea, and having no direct connection with 
it. It grew, he said, on the stems of aquatic plants. It 
was quite new to me, and I was advised to send it to Pro- 
fessor Allman, of Trinity College, Dublin, who is preparing 
