J)ENDROSOMA EAJJIANS, EHKENEEKG. 
177 
soma differs from Trichophrya and Lerumoplirya are 
its greater size, the greater length of its arms, and the 
characters of the gemmula. The suckers of Dendrosoma 
vary a great deal in length, according to circumstances, but 
they never attain to the same actual or relative length as the 
suckers of Lernasophry a. The free-swimming gemmulm 
of Dendrosoma differ from the n'emmulm which we attribute 
O 
to Lernmophrya in size, in shape, in having several instead 
of only three or four bands of cilia, and in having several 
contractile vacuoles instead of only three. 
A prolonged study of the specimens of Dendrosoma from 
the Bridgewater canal and from Birmingham give some 
grounds for the view that they belong to different species. 
These differences have been jn-eviously mentioned (p. 147) ; 
it is only necessary in this place to refer again to the difference 
in the number of the micronuclei. In looking through a 
number of preparations of specimens from the tw'o localities, 
the large number of the micronuclei iu the Birmingham speci- 
mens is often a very .striking feature. To take two extreme 
ca.ses, the piece of an arm that is drawn iu fig. 15 showing 
nineteen micronuclei in a clu.ster round the meganucleus, and 
a gemmula showing seven micronuclei, such as that drawn in 
fig. U), we should recognise at once as belonging almost 
certainly to the Birmingham variety. On the other hand, 
when the micronuclei are isolated or in pairs at considerable 
distances apart, as shown in text-fig. 1 and in figs. 9 and lU, 
there would be a strong probability that they were taken from 
specimens of the Bridgewater canal variety. 
But nevertheless specimens of the canal variety are some- 
times found iu which several microuuclei are aggregated 
together, as shown, tor instance, in fig. 8, where six micro- 
nuclei form a cluster, and in many specimens from Birming- 
ham the microuuclei are scattered iu very much the same way 
as in the canal variety. 
To endeavour, therefore, to make a specific character of the 
number of the micronuclei, a character which is obviously 
subject to great variation, would be a task of great difficulty 
