DINOPHILUS, rOLTCORDIUS, ECHIUBUS, AND I'HORONIS. 113 
flagellum, lias its own nucleus. This latter state might be 
reached by a multiplication of the nuclei until they came to 
correspond in number with the tubes. That Dinophilus is 
related to Polygordius has long been suspected; it is there- 
foi’e interesting to note that in the larval nephridium of 
Polygordius there is a similar multiplicity of tubes, as I 
showed some years ago (2). 
The Larva op Echidrus. 
It is to Hatschek that we owe the first detailed description 
of the larval nepliridia of Echiurns (6). According to his 
account there are a pair of larval nepliridia withont internal 
opening. In the late larva there is a membrane separating 
the coelom near the gut from a space below the body-wall 
traversed by mesenchyniatous strands. Hatschek describes 
the nephridium as passing inwards from its external pore 
through tins space, to spread out in a system of fine branches 
on the outer surface of the membrane. The nephridium ends 
in “ein Hiishel von Ihidorganen,” and die Endknopfehen 
der fei listen Caniilchen je einen Zellkern enthalten.” 
'I'his description and the accompanying figures had long 
led me to suspect that the “ Endkndpfchen ’’ were in reality 
“ solenocytes.” It was not, however, till this spring that I 
had an opportunity of confirming my suspicions by the exami- 
nation of living larva3 at Naples. 
Fig. 3 is a careful drawing from life of the nephridium of 
a larva of about the a^e shown in Hatschek’s fisf. 4. A 
glance at my figure shows that the nephridium is, in fact, 
provided with typical solenocytes. The canal leading from 
the external pore has granular, rather thick walls; when it 
reaches the membrane outside the cceloniic epithelium it 
divides into a number of thin-walled branches, which spread 
over the membrane. These terminate in delicate, almost 
cylindrical tubes, at the end of which are the nucleated cell- 
bodies. 'I'he nuclei can be seen even in the living state. 
As figured by Hatschek, fine protoplasmic threads extend 
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