49 
superficially over the ventral surface of the next segment 
to the integument. At the end of the 4th segment not only 
are there a pair of sensory branches given to the rudimen- 
tory appendages, but just before a pair are given off to the 
two large ventral muscles (originating from the sternum of 
the 5tlr segment), on which each ends in a beautiful 
nucleated Doyerian eminence. In the 1 st abdominal seg- 
ment is the fork described by the two German observers, 
but this takes its origin from the superficial (ventral) aspect 
of the cord which is continued onwards under the colleterial 
gland. After running obliquely outwards each branch of 
the fork subdivides into two, an anterior sensory and a 
posterior muscular branch. At the commencement of the 
third abdominal segment the ventral cord forks, its branches 
diverge slightly in this segment, but more in the next, 
rising to the sides of the intestine, and having the ventral 
muscles of this segment superficial to them. In the last 
segment they have left the intestine and run about the 
horizontal median plane straight into the axis of either 
branch of the furca. I have only been able to detect two 
crystal spheres in the eye of Cyclops; the anterior one in 
Cyclopsine is here absent. 
What seemed to me to be pits with a small mouth so as 
to form a nearly complete sphere occurring in the rudimen- 
tary legs of the last thoracic segment are probably sense 
organs. 
The ventral cord in Cyclopoids contains the elongated 
nuclei everywhere found on nerve cords, but no ganglion 
cells ; it has lost its significance as a sense organ, and is purely 
commissural. No transverse commissures are found any- 
where, even after its bifurcation. The cells on the sensory 
nerve fibres suggest a functional displacement outward of 
the local nerve centres. 
Note added January 20th, 1879 ; 
In the above abstract I have referred to a vesicle seated at 
