1887.] Mr Cunningham on Nephridia of Lanice conchilega. 239 
loop being connected with the nephrostome, while the outer passes 
downwards and opens into a longitudinal tube common to all the 
four nepliridia of a side. Four openings, corresponding to the four 
nephridia, place the longitudinal tube in communication with the 
exterior ; these openings are close behind the upper ends of the 
2nd to the 5th uncinigerous tori respectively ; the 1st uncinigerous 
torus being in the 5th somite. The longitudinal tube is continued 
backwards on each side through somites 10-13, representing four 
more coalesced nephridia ; but in this region there are neither 
internal nor external openings, nor any loops similar to those in 
the more interior region ; the longitudinal tube is simple, almost 
cylindrical, showing slight indentations between the successive 
somites, which mark where the successive nephridia have coalesced. 
The outer side of the whole longitudinal tube is in contact with 
the ventral longitudinal muscles, while the upper and inner side is 
beneath the oblique muscles. The internal openings already men- 
tioned are situated immediately behind the notopodial fascicles 
of setse of somites 5-8 inclusive. The longitudinal tube extends 
into the 5th somite, but I could not find there an external opening. 
Behind the 1st to the 4th somites are traces of incomplete septa, 
of which that behind the 4th is the most complete. Attached to 
the front of the latter septum is a nephrostome, but I could not 
trace any connection between this and the part of the tube in the 
5th somite. There are two other well-marked nephrostomata 
attached to the septa behind somites 2 and 3, and these openings 
lead into tubes seen in somites 3 and 4. I could not find external 
openings in the two latter somites. There are thus eleven nephridia 
represented altogether, — three rudimentary, in somites 3, 4, 5 ; four 
perfect, in somites 6-9 ; and four imperfect, in somites 10-13 ; the 
eight posterior being all in communication, their distal parts 
having fused to form a longitudinal tube. This is the first case 
in wdiich such a longitudinal coalescence of nephridia has been 
discovered, and its morphological similarity to the condition in 
Vertebrates is obvious. 
The Astronomer-Royal for Scotland exhibited specimens illus- 
trating Ives’s process of Isochromatic Photography. 
By permission of the Meeting, Professor Tait stated to the Society 
• vol. xiv. 3/11/87 Q 
