SOME ABNORMAL ANNELIDS. 439 
these abnormal rings 74 and 75. As far as could be made out 
by dissection and by section the arrangement of the septa was 
as indicated in the diagram, fig. 5. A large septum appears to 
separate 74 from 75 internally and to correspond to the external 
groove between those two peculiar rings. The body-cavity of 
75 is bifurcated like its wall and its contents, supplying the base 
of each terminal, and is separated from the somites 76 and 1 of 
the two terminals by two distinct, complete septa. While this 
ring is not subdivided internally, the anterior one, 74, presents 
on the left four small,incomplete septa extending from the body- 
wall to the digestive tract, as seen in fig. 5. Each compart- 
ment of the body-cavity so formed has its own cluster of small 
sete, five pairs in place of one on this left side. On the right 
side no setz could be found 
The nephridia that are normally present in both terminals, as 
indicated in fig. 5, seem to be absent in 75 on its right, where 
we would expect one either posterior to or anterior to the 
branch of the intestine that runs out into the right terminal ; 
it may have been displaced and not recognised in the serial 
sections. The nephridia of 74 are multiplied on the left to 
correspond to the number of subdivisions of the body-cavity, 
five nephridia taking the place of one. 
One other abnormality shown in the diagram should be 
mentioned, as it makes the exception to the rule that all the 
abnormalities are within the two rings 74 and 75; the ring 1 
of the right terminal has no nephridium upon the left side, as 
far as could be ascertained. 
The ring 75 thus bears both the terminals and contains all 
the bifurcated organs ; it appears to be a single somite. 
The ring 74 is single upon the right but subdivided upon the 
left. From the small size and apparent newness of these small 
septa and sete we may judge them to have been interpolated 
here to make what were else a normal ring so much longer 
upon the left than upon the right. If this elongation of the 
left side of 74 were non-existent the two terminals would appear, 
obviously, as two sister structures or as a bifurcation of the 
main axis, not as a main terminal and a side outgrowth. 
