HRE 
DA 
ONE OF OUR COMMON MONADS. 
BY PROF. ALBERT H. TUTTLE.* ie 
Since the investigations of Clark, Carter and others on 
sponges and their allies, anything which adds to our knowledge of 
has been known. a 
Until recently but little has been known of the real nature ot 
the Monadina. As a natural consequence, organisms have mA 
referred to the different genera of this family upon very slight 
study and superficial Te 
i ae semblances.: Urella, ' 
which Ehrenberg 
scribes thus, “ aggregate 
monads, free-swimming: 
YN tailless, devoid 
N eyespeck and ha 
ay 1 AZ gelliform fil 
Re oe 
e ae ~ share of attention 
if S one might 
A colony of about forty Monads. the ‘species 
figures given that the diagnosis of the genus had been 2 
very minute, aggregated, free-swimming,” — whether 7 
or Alga making no difference. 
When, therefore, I found in a collection made at Spy 
Cambridge, on the 25th of November last, a large eri 
viduals of this genus (probably the species gla 
made use of the opportunity for a careful eke 
my spare time to it daily as long as I continued to? 
water; what follows is therefore the result of @ 
vations, at which each point has been examined and ve 
* Communicated to the Section of Microscopy of the Boston society = 
tory, Dec. 13th, 1871, 
(286) 
