4 Mr. W. Saville Kent on Prof. E. Haeckel’s 
communication, already quoted, it will be found that the record 
of nearly forty well-marked species, in place of the original 
four, has been the reward of my several years’ study of this 
interesting group; and concerning the general structure, func- 
tions, and developmental history of these I am enabled to 
supply perfectly original and important data. To those 
acquainted with the writings of Prof. Clark, the general aspect 
of these typical “ collar-bearing’’ monads will no doubt be 
familiar ; but for the advantage of those who are not, they may 
be described as ovate, pyriform, or flask-shaped animalcules, 
stalked, sessile, or floating freely in the water, naked or en- 
closed within a transparent lorica, and either solitary or 
forming extensive colonies—the chief and common character- 
istic of all these being that each individual is adorned ante- 
riorly with an exquisitely delicate funnel-shaped sarcodic 
expansion, the “ collar,” from the centre of the area en- 
closed by the base of which a single long flagellum takes its 
origin. All the species as yet discovered are of so minute 
a size, the body of the largest not exceeding the 1200th part 
of an English inch in total length, and usually being much 
smaller, that a magnifying-power of at least 500 diameters is 
requisite for their satisfactory investigation. This last cir- 
cumstance, no doubt, readily accounts for the immunity from 
attention that they have hitherto enjoyed, they, on the other 
hand, being so abundantly distributed in both salt and fresh 
water that scarcely a fragment of weed can be examined from 
either of these two sources, by those once familiar with their ap- 
pearances, and employing a sufficiently high magnifying- 
power, without the encounter of some one or even several 
types. 
Among the most important results of my investigations of 
this interesting and, as is now shown, exceedingly extensive 
group is the satisfactory elucidation of the true nature and 
position of the oral aperture or mouth, and of the structure 
and function of the hyaline funnel-shaped “ collar.” Prof. 
Clark left both these points in a very unsatisfactory state, he, 
in the first place, being altogether unable to determine the 
exact aspect and position of the oral aperture, but hazarding 
the opinion that it lay somewhere within the collar and near 
the base of the flagellum. Concerning the nature and uses 
of the funnel-shaped “ collar” itself he makes no suggestion 
and furnishes us with no clue. By prolonged and repeated 
observation, however, I have been able most conclusively to 
demonstrate that food is ingested at any point within the area 
embraced by the base of the hyaline collar, the whole of | 
which area must therefore necessarily be characterized as the 
