1887 .] 
Mr Frank E. Beddard on Earthworms. 
163 
after the clitellar segments, if not earlier, the setse have a partly 
regular, partly irregular arrangement. The ventral setse of eacli 
pair have a fixed position, and correspond for a large number of 
consecutive segments ; the dorsal setse of each pair are, on the 
contrary, quite irregular in their disposition. There appears to be 
no regular alternation in their arrangement ; it sometimes happens 
that the seta of two consecutive segments will correspond in 
position, sometimes the setse of one segment, and the next but 
one or next but two, &c., that it is impossible to lay down any 
general statements. The two halves of the body are not symmetrical 
in respect of their setse. In the hinder part of the body there is 
a perfectly regular alternation of the setse from segment to segment; 
each seta of one segment is exactly between two setse of the 
preceding and consecutive segments ; and this statement applies to 
all the setse in that region of the body, hence there are exactly 
sixteen rows in this region of the body, while there are a great 
many more anteriorly. 
In U. corethrurus the setse of the anterior segments are disposed 
regularly and in pairs ; but the two setse of each pair do not appear 
from Perrier’s description to be so closely applied as in my species. 
They agree in the fact that in the posterior part of the body the 
setse regularly alternate, each seta being placed between two setse of 
the preceding and succeeding segments. Perrier, however, says 
nothing about the disposition of the setse in the middle portion of 
the body. I must assume, therefore, for the present that the 
remarkable arrangement of the setse of my Urocliceta in this, by far 
the greater portion of the body, is peculiar to that species, and dis- 
tinguishes it from Urocliceta corethrurus. Dr Horst’s description 
of Urocliceta d-ubia seems to show that this species differs but little 
in this particular respect from U. corethrurus. 
With regard to the shape of the setse, I have to record an 
important difference from U. corethrurus. Perrier describes and 
figures the setse in the latter species as being bifid at their free 
extremity, and dwells upon the similarity in this respect to the 
Naidea. Horst says nothing about the structure of the setse in 
U. dubia. In my species I did not succeed in observing any 
bifurcation of the distal extremity of the setse ; these structures are, 
in fact, precisely similar to those of other earthworms. This differ- 
